stl使用例子

S ample of STL
STL 范例(一)
容器部分
Vector-------------------------------------------1
Deque--------------------------------------------------20
List---------------------------------------------------38
Set-----------------------------------------------------66
Multiset------------------------------------------------88
Map-----------------------------------------------------98
Multimap-----------------------------------------------113
Stack---------------------------------------------------136
Queue---------------------------------------------------138
Priority_queue------------------------------------------139
Copyright: anatoliyurb Edited by snowman
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Vector
constructors
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
int main ()
{
string str[]={"Alex","John","Robert"};
// empty vector object
vector<int> v1;
// creates vector with 10 empty elements
vector<int> v2(10);
// creates vector with 10 elements,
// and assign value 0 for each
vector<int> v3(10,0);
// creates vector and assigns
// values from string array
vector<string> v4(str+0,str+3);
vector<string>::iterator sIt = v4.begin();
while ( sIt != v4.end() )
cout << *sIt++ << " ";
cout << endl;
// copy constructor
vector<string> v5(v4);
for ( int i=0; i<3; i++ )
cout << v5[i] << " ";
cout << endl;
return 0;
}
OUTPUT:
// Alex John Robert
// Alex John Robert
assign
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
Copyright: anatoliyurb Edited by snowman
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int main ()
{
int ary[]={1,2,3,4,5};
vector<int> v;
// assign to the "v" the contains of "ary"
v. assign(ary,ary+5);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
// replace v for 3 copies of 100
v. assign(3,100);
copy(v.begin(),v.end(),
ostream_iterator(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 100 100 100
at
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
vector<int> v(3,0);
v[0] = 100;
v. at(1) = 200;
for ( int i=0; i<3; i++ )
cout << v. at(i) << " ";
cout << endl;
return 0;
}
OUTPUT:
// 100 200 0
back
#include <iostream>
#include <vector>
Copyright: anatoliyurb Edited by snowman
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#include <string>
#include <iterator>
using namespace std;
template<class T, class D>
class Member
{
public:
Member(T t, D d) : name(t), sal(d) {}
void print();
private:
T name;
D sal;
};
template<class T, class D>
void Member::print()
{
cout << name << " " << sal << endl;
}
//======================================
int main ()
{
typedef Member<string,double> M;
vector<M> v;
v.push_back(M("Robert",60000));
v.push_back(M("Linda",75000));
vector<M>::iterator It = v.begin();
cout << "Entire vector:" << endl;
while ( It != v.end() )
(It++)->print();
cout << endl;
cout << "Return from back()" << endl;
v. back().print();
return 0;
}
OUTPUT:
// Entire vector:
// Robert 60000
// Linda 75000
//
// Return from back()
// Linda 75000
begin
Copyright: anatoliyurb Edited by snowman
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#include <iostream>
#include <vector>
#include <iterator>
#include <numeric>
using namespace std;
int main ()
{
vector<int> v(5);
iota(v. begin(),v.end(),1);
vector<int>::iterator It = v. be gin();
while ( It != v.end() )
cout << *It++ << " ";
cout << endl;
// third element of the vector
It = v. begin()+2;
cout << *It << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 3
capacity
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
vector<int> v(10);
cout << "Size of v = "
<< v.size() << endl;
cout << "Capacity of v = "
<< v. capacity() << endl;
v.resize(100);
cout << "After resizing:" << endl;
cout << "Size of v = "
<< v.size() << endl;
cout << "Capacity of v = "
<< v. capacity() << endl;
return 0;
Copyright: anatoliyurb Edited by snowman
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}
OUTPUT:
// Size of v = 10
// Capacity of v = 10
// After resizing:
// Size of v = 100
// Capacity of v = 100
clear
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//==============================
int main ()
{
vector<int> v(10);
Print<int> print;
fill(v.begin(),v.end(),5);
cout << "Vector v : ";
for_each(v.begin(),v.end(),print);
cout << endl;
cout << "Size of v = " << v.size()
<< endl;
cout << "v.clear" << endl;
v. clear();
cout << "Vector v : ";
for_each(v.begin(),v.end(),print);
cout << endl;
cout << "Size of v = " << v.size()
<< endl;
cout << "Vector v is ";
v.empty() ? cout << "" : cout << "not ";
Copyright: anatoliyurb Edited by snowman
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cout << "empty" << endl;
return 0;
}
// Vector v : 5 5 5 5 5 5 5 5 5 5
// Size of v = 10
// v.clear
// Vector v :
// Size of v = 0
// Vector v is empty
empty
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
vector<int> v;
cout << "Vector is ";
v.e e mpty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
v.push_back(100);
cout << "Vector is ";
v. empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
return 0;
}
// Vector is empty
// Vector is not empty
end
#include <iostream>
#include <vector>
#include <iterator>
#include <numeric>
using namespace std;
int main ()
{
vector<int> v(5);
Copyright: anatoliyurb Edited by snowman
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iota(v.begin(),v. end(),1);
vector<int>::iterator It = v.begin();
while ( It != v. end() )
cout << *It++ << " ";
cout << endl;
// last element of the vector
It = v. end()-1;
cout << *It << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 5
erase
#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>
using namespace std;
int main ()
{
vector<int> v(10);
vector<int>::iterator It;
for ( int i=0; i<10; i++ )
v[i] = i+1;
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
It = v.begin()+2;
// remove third element
v. erase(It);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
It = v.begin();
// remove 2 elements from beginning fo v
v. erase(It,It+2);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
Copyright: anatoliyurb Edited by snowman
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return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
// 1 2 4 5 6 7 8 9 10
// 4 5 6 7 8 9 10
front
#include <iostream>
#include <vector>
#include <string>
#include <iterator>
using namespace std;
template<class T, class D>
class Member
{
public:
Member(T t, D d) : name(t), sal(d) {}
void print();
private:
T name;
D sal;
};
template<class T, class D>
void Member::print()
{
cout << name << " " << sal << endl;
}
//======================================
int main ()
{
typedef Member<string,double> M;
vector<M> v;
v.push_back(M("Linda",75000));
v.push_back(M("Robert",60000));
vector<M>::iterator It = v.begin();
cout << "Entire vector:" << endl;
while ( It != v.end() )
(It++)->print();
cout << endl;
cout << "Return from front()" << endl;
v. front().print();
Copyright: anatoliyurb Edited by snowman
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return 0;
}
OUTPUT:
// Entire vector:
// Linda 75000
// Robert 60000
//
// Return from front()
// Linda 75000
insert
#include <iostream>
#include <vector>
#include <iterator>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
int ary[5];
fill(ary,ary+5,1);
vector<int> v;
vector<int>::iterator It;
Print<int> print;
copy(ary,ary+5,
back_inserter(v));
cout << "vector v : ";
for_each(v.begin(),v.end(),print);
cout << endl;
It = v.begin();
// insert value "5" at the position "It"
cout << "v.insert(It,5) : ";
v. insert(It,5);
for_each(v.begin(),v.end(),print);
Copyright: anatoliyurb Edited by snowman
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cout << endl;
// insert range ary+2 - ary+5 at the position "It"
It = v.begin()+5;
cout << "v.insert(It,ary+2,ary+5 : ";
v. insert(It,ary+2,ary+5);
for_each(v.begin(),v.end(),print);
cout << endl;
// insert 2 value of "20" at the position "It"
It = v.end()-2;
cout << "v.insert(It,2,20) : ";
v. insert(It,2,20);
for_each(v.begin(),v.end(),print);
cout << endl;
return 0;
}
OUTPUT:
// vector v : 1 1 1 1 1
// v.insert(It,5) : 5 1 1 1 1 1
// v.insert(It,ary+2,ary+5 : 5 1 1 1 1 1 1 1 1
// v.insert(It,2,20) : 5 1 1 1 1 1 1 20 20 1 1
max_size
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
vector<int> v(10);
cout << "Size of v = "
<< v.size() << endl;
cout << "Max_size of v = "
<< v. max _size() << endl;
return 0;
}
OUTPUT:
// Size of v = 10
// Max_size of v = 1073741823
pop_back
#include <iostream>
Copyright: anatoliyurb Edited by snowman
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#include <vector>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
vector<int> v;
Print<int> print;
for ( int i=0; i<5; i++ )
v.push_back(i+1);
while ( !v.empty() )
{
for_each(v.begin(),v.end(),print);
cout << endl;
v. pop_back();
}
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 1 2 3 4
// 1 2 3
// 1 2
// 1
push_back
#include <iostream>
#include <vector>
#include <string>
#include <iterator>
using namespace std;
template <class T>
class Name
Copyright: anatoliyurb Edited by snowman
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{
public:
Name(T t) : name(t) {}
void print()
{
cout << name << " ";
}
private:
T name;
};
//=============================
int main ()
{
typedef Name<string> N;
typedef vector<N> V;
V v;
N n1("Robert");
N n2("Alex");
v. push_back(n1);
v. push_back(n2);
// unnamed object of the type Name
v. push_back(N("Linda"));
V::iterator It = v.begin();
while ( It != v.end() )
(It++)->print();
cout << endl;
return 0;
}
OUTPUT:
// Robert Alex Linda
rbegin and rend
#include <iostream>
#include <iomanip>
#include <vector>
#include <string>
#include <algorithm>
#include <iterator>
using namespace std;
class ID
{
Copyright: anatoliyurb Edited by snowman
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friend bool operator < ( const ID&, const ID& );
public:
ID(string name,int score) : name(name), score(score) {}
void display ()
{
cout.setf(ios::left);
cout << setw(3) << score << name << endl;
}
private:
string name; int score;
};
//-----------------------------------------------------
// comperation function for sorting
bool operator < ( const ID& a, const ID& b )
{
return a.score < b.score;
}
//-----------------------------------------------------
typedef vector<ID> Vector; // new name for existing datatype
int main ()
{
Vector v;
Vector::iterator Iter;
v.push_back(ID("Smith A",96));
v.push_back(ID("Amstrong B.",91));
v.push_back(ID("Watson D.",82));
for ( Iter = v.begin(); Iter != v.end(); Iter++ )
Iter->display();
sort(v.begin(),v.end()); // sort algorithm
cout << endl << "Sorted by Score" << endl;
cout << "===============" << endl;
for ( Iter = v.begin(); Iter != v.end(); Iter++ )
Iter->display();
cout << endl << "Reverse output" << endl;
cout << "===============" << endl;
Vector::reverse_iterator r = v. rbegin();
while ( r != v. rend() )
cout << r->display();
cout << endl;
return 0;
Copyright: anatoliyurb Edited by snowman
- 15 -
}
OUTPU T:
// 96 Smith A.
// 91 Amstrong B.
// 82 Watson D.
//
// Sorted by Score
// ===============
// 82 Watson D.
// 91 Amstrong B.
// 96 Smith A.
//
// Reverse output
// ===============
// 96 Smith A.
// 91 Amstrong B.
// 82 Watson D.
reserve
#include <iostream>
#include <vector>
using namespace std;
int main ()
{
vector<int> v(5,0); // 5 elements, each - value 0
/*------------------------------------------------*/
cout << "Size of v = " << v.size() << endl;
cout << "Capacity v = " << v.capacity() << endl;
cout << "Value of each element is - ";
for ( int i = 0; i < v.size(); i++ )
cout << v[i] << " ";
cout << endl;
v[0] = 5; // new value for first element
v[1] = 8;
v.push_back(3); // creates new (6th) element of vector,
v.push_back(7); // automatically increases size
cout << endl; // capacity of vector v
cout << "Size of v = " << v.size() << endl;
cout << "Capacity v = " << v.capacity() << endl;
cout << "Value of each element is - ";
for ( int i = 0; i < v.size(); i++ )
Copyright: anatoliyurb Edited by snowman
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cout << v[i] << " ";
cout << endl << endl;
v. reserve(100); // increase capacity to 100
cout << "Size of v1_int = " << v.size() << endl;
cout << "Capacity v1_int = " << v.capacity() << endl;
int size = sizeof(v); // how big is vector itself
cout << "sizeof v = " << size << endl;
return 0;
}
OUTPUT:
// Size of v = 5
// Capacity v = 5
// Value of each element is - 0 0 0 0 0
//
// Size of v = 7
// Capacity v = 10
// Value of each element is - 5 8 0 0 0 3 7
//
// Size of v = 7
// Capacity v = 100
// sizeof v = 12
resize
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
int main ()
{
vector<int> v(5);
for ( int i=0; i<5; i++ )
v[i] = i*2;
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
v. resize(7,100);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
Copyright: anatoliyurb Edited by snowman
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cout << endl;
v. resize(4);
copy(v.begin(),v.end(),
ostream_iterator<int>(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 0 2 4 6 8
// 0 2 4 6 8 100 100
// 0 2 4 6
size
#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
vector<char> v(5);
Print<char> print;
cout << "Size of v = " << v. size() << endl;
fill(v.begin(),v.end(),‘*‘);
for_each(v.begin(),v.end(),print);
cout << endl;
for ( int i=0; i < v. size(); i++ )
cout << v[i] << " ";
cout << endl;
for ( int i=0; i<5; i++ )
{
Copyright: anatoliyurb Edited by snowman
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cout << "Size of v = ";
for_each(v.begin(),v.end(),print);
cout << endl;
v.pop_back();
}
return 0;
}
OUTPUT:
// Size of v = 5
// * * * * *
// * * * * *
// Size of v = * * * * *
// Size of v = * * * *
// Size of v = * * *
// Size of v = * *
// Size of v = *
swap
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
int ary[] = {1,2,3,4,5,6,7,8,9,10};
Print print;
vector<int> v1(ary,ary+7);
vector<int> v2(ary+7,ary+10);
cout << "Vector v1 : ";
for_each(v1.begin(),v1.end(),print);
cout << endl;
Copyright: anatoliyurb Edited by snowman
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cout << "Size of v1 = " << v1.size()
<< endl << endl;
cout << "Vector v2 : ";
for_each(v2.begin(),v2.end(),print);
cout << endl;
cout << "Size of v2 = " << v2.size()
<< endl << endl;
v1. swap(v2);
cout << "After swapping:" << endl;
cout << "Vector v1 : ";
for_each(v1.begin(),v1.end(),print);
cout << endl;
cout << "Size of v1 = " << v1.size()
<< endl << endl;
cout << "Vector v2 : ";
for_each(v2.begin(),v2.end(),print);
cout << endl;
cout << "Size of v2 = " << v2.size()
<< endl << endl;
return 0;
}
OUTPUT:
// Vector v1 : 1 2 3 4 5 6 7
// Size of v1 = 7
//
// Vector v2 : 8 9 10
// Size of v2 = 3
//
// After swapping:
// Vector v1 : 8 9 10
// Size of v1 = 3
//
// Vector v2 : 1 2 3 4 5 6 7
// Size of v2 = 7
Copyright: anatoliyurb Edited by snowman
- 20 -
Deque
constructors
#include <iostream>
#include <deque>
#include <string>
#include <algorithm>
using namespace std;
int main ()
{
string str[]={"Alex","John","Robert"};
// empty deque object
deque<int> d1;
// creates deque with 10 empty elements
deque<int> d2(10);
// creates deque with 10 elements,
// and assign value 0 for each
deque<int> d3(10,0);
// creates deque and assigns
// values from string array
deque<string> d4(str+0,str+3);
deque<string>::iterator sIt = d4.begin();
while ( sIt != d4.end() )
cout << *sIt++ << " ";
cout << endl;
// copy constructor
deque<string> d5(d4);
for ( int i=0; i<3; i++ )
cout << d5[i] << " ";
cout << endl;
return 0;
}
OUTPUT:
// Alex John Robert
// Alex John Robert
Copyright: anatoliyurb Edited by snowman
- 21 -
assign
#include <iostream>
#include <deque>
#include <algorithm>
#include <iterator>
using namespace std;
int main ()
{
int ary[]={1,2,3,4,5};
deque<int> d;
// assign to the "d" the contains of "ary"
d. assign(ary,ary+5);
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
// replace d for 3 copies of 100
d. assign(3,100);
copy(d.begin(),d.end(),
ostream_iterator(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 100 100 100
at
#include <iostream>
#include <deque>
using namespace std;
int main ()
{
deque<int> d(3,0);
d[0] = 100;
d. at(1) = 200;
for ( int i=0; i<3; i++ )
Copyright: anatoliyurb Edited by snowman
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cout << d. at(i) << " ";
cout << endl;
return 0;
}
OUTPUT:
// 100 200 0
back
#include <iostream>
#include <deque>
#include <string>
#include <iterator>
using namespace std;
template<class T, class D>
class Member
{
public:
Member(T t, D d) : name(t), sal(d) {}
void print();
private:
T name;
D sal;
};
template<class T, class D>
void Member::print()
{
cout << name << " " << sal << endl;
}
//======================================
int main ()
{
typedef Member<string,double> M;
deque<M> d;
d.push_back(M("Robert",60000));
d.push_back(M("Linda",75000));
deque<M>::iterator It = d.begin();
cout << "Entire deque:" << endl;
while ( It != d.end() )
(It++)->print();
cout << endl;
cout << "Return from back()" << endl;
Copyright: anatoliyurb Edited by snowman
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d. back().print();
return 0;
}
OUTPUT:
// Entire deque:
// Robert 60000
// Linda 75000
//
// Return from back()
// Linda 75000
begin
#include <iostream>
#include <deque>
#include <iterator>
#include <numeric>
using namespace std;
int main ()
{
deque<int> d(5);
iota(d. begin(),d.end(),1);
deque<int>::iterator It = d. begin();
while ( It != d.end() )
cout << *It++ << " ";
cout << endl;
// third element of the deque
It = d. begin()+2;
cout << *It << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 3
clear
#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;
Copyright: anatoliyurb Edited by snowman
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template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//==============================
int main ()
{
deque<int> d(10);
Print<int> print;
fill(d.begin(),d.end(),5);
cout << "Deque d : ";
for_each(d.begin(),d.end(),print);
cout << endl;
cout << "Size of d = " << d.size()
<< endl;
cout << "d.clear" << endl;
d. clear();
cout << "Deque d : ";
for_each(d.begin(),d.end(),print);
cout << endl;
cout << "Size of d = " << d.size()
<< endl;
cout << "Deque d is ";
d.empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
return 0;
}
// Deque d : 5 5 5 5 5 5 5 5 5 5
// Size of d = 10
// d.clear
// Deque d :
// Size of d = 0
// Deque d is empty
empty
#include <iostream>
Copyright: anatoliyurb Edited by snowman
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#include <deque>
using namespace std;
int main ()
{
deque<int> d;
cout << "Deque is ";
d. empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
d.push_back(100);
cout << "Deque is ";
d. empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
return 0;
}
// Deque is empty
// Deque is not empty
end
#include <iostream>
#include <deque>
#include <iterator>
#include <numeric>
using namespace std;
int main ()
{
deque<int> d(5);
iota(d.begin(),d. end(),1);
deque<int>::iterator It = d.begin();
while ( It != d. end() )
cout << *It++ << " ";
cout << endl;
// last element of the deque
It = d. end()-1;
cout << *It << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 5
erase
Copyright: anatoliyurb Edited by snowman
- 26 -
#include <iostream>
#include <deque>
#include <iterator>
#include <algorithm>
using namespace std;
int main ()
{
deque<int> d(10);
deque<int>::iterator It;
for ( int i=0; i<10; i++ )
d[i] = i+1;
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
It = d.begin()+2;
// remove third element
d. erase(It);
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
It = d.begin();
// remove 2 elements from beginning fo d
d. erase(It,It+2);
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
// 1 2 4 5 6 7 8 9 10
// 4 5 6 7 8 9 10
front
#include <iostream>
#include <deque>
#include <string>
#include <iterator>
using namespace std;
template<class T, class D>
Copyright: anatoliyurb Edited by snowman
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class Member
{
public:
Member(T t, D d) : name(t), sal(d) {}
void print();
private:
T name;
D sal;
};
template<class T, class D>
void Member::print()
{
cout << name << " " << sal << endl;
}
//======================================
int main ()
{
typedef Member<string,double> M;
deque<M> d;
d.push_back(M("Linda",75000));
d.push_back(M("Robert",60000));
deque<M>::iterator It = d.begin();
cout << "Entire deque:" << endl;
while ( It != d.end() )
(It++)->print();
cout << endl;
cout << "Return from front()" << endl;
d. front().print();
return 0;
}
OUTPUT:
// Entire deque:
// Linda 75000
// Robert 60000
//
// Return from front()
// Linda 75000
insert
Copyright: anatoliyurb Edited by snowman
- 28 -
#include <iostream>
#include <deque>
#include <iterator>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
int ary[5];
fill(ary,ary+5,1);
deque<int> d;
deque<int>::iterator It;
Print<int> print;
copy(ary,ary+5,
back_inserter(d));
cout << "deque d : ";
for_each(d.begin(),d.end(),print);
cout << endl;
It = d.begin();
// insert value "5" at the position "It"
cout << "d.insert(It,5) : ";
d. insert(It,5);
for_each(d.begin(),d.end(),print);
cout << endl;
// insert range ary+2 - ary+5 at the position "It"
It = d.begin()+5;
cout << "d.insert(It,ary+2,ary+5 : ";
d. insert(It,ary+2,ary+5);
for_each(d.begin(),d.end(),print);
cout << endl;
// insert 2 value of "20" at the position "It"
It = d.end()-2;
cout << "d.insert(It,2,20) : ";
Copyright: anatoliyurb Edited by snowman
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d. insert(It,2,20);
for_each(d.begin(),d.end(),print);
cout << endl;
return 0;
}
OUTPUT:
// deque d : 1 1 1 1 1
// d.insert(It,5) : 5 1 1 1 1 1
// d.insert(It,ary+2,ary+5 : 5 1 1 1 1 1 1 1 1
// d.insert(It,2,20) : 5 1 1 1 1 1 1 20 20 1 1
max_size
#include <iostream>
#include <deque>
using namespace std;
int main ()
{
deque<int> d(10);
cout << "Size of d = "
<< d.size() << endl;
cout << "Max_size of d = "
<< d. max_size() << endl;
return 0;
}
OUTPUT:
// Size of d = 10
// Max_size of d = 1073741823
pop_back
#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
Copyright: anatoliyurb Edited by snowman
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void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
deque<int> d;
Print<int> print;
for ( int i=0; i<5; i++ )
d.push_back(i+1);
while ( !d.empty() )
{
for_each(d.begin(),d.end(),print);
cout << endl;
d. pop_back();
}
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 1 2 3 4
// 1 2 3
// 1 2
// 1
pop_front
#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
Copyright: anatoliyurb Edited by snowman
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int main ()
{
deque<int> d;
Print<int> print;
for ( int i=0; i<5; i++ )
d.push_back(i+1);
while ( !d.empty() )
{
for_each(d.begin(),d.end(),print);
cout << endl;
d. pop_front();
}
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 2 3 4 5
// 3 4 5
// 4 5
// 5
push_back
#include <iostream>
#include <deque>
#include <string>
#include <iterator>
using namespace std;
template <class T>
class Name
{
public:
Name(T t) : name(t) {}
void print()
{
cout << name << " ";
}
private:
T name;
};
//=============================
int main ()
Copyright: anatoliyurb Edited by snowman
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{
typedef Name<string> N;
typedef deque<N> D;
D d;
N n1("Robert");
N n2("Alex");
d. push_b ack(n1);
d. push_back(n2);
// unnamed object of the type Name
d. push_back(N("Linda"));
D::iterator It = d.begin();
while ( It != d.end() )
(It++)->print();
cout << endl;
return 0;
}
OUTPUT:
// Robert Alex Linda
push_front t
#include <iostream>
#include <deque>
#include <string>
#include <iterator>
using namespace std;
template <class T>
class Name
{
public:
Name(T t) : name(t) {}
void print()
{
cout << name << " ";
}
private:
T name;
};
//=============================
int main ()
{
typedef Name<string> N;
typedef deque<N> D;
Copyright: anatoliyurb Edited by snowman
- 33 -
D d;
N n1("Robert");
N n2("Alex");
d. push_front(n1);
d. push_front(n2);
// unnamed object of the type Name
d. push_front(N("Linda"));
D::iterator It = d.begin();
while ( It != d.end() )
(It++)->print();
cout << endl;
return 0;
}
OUTPUT:
// Linda Alex Robert
rbegin and rend
#include <iostream>
#include <iomanip>
#include <deque>
#include <string>
#include <algorithm>
#include <iterator>
using namespace std;
class ID
{
friend bool operator < ( const ID&, const ID& );
public:
ID(string name,int score) : name(name), score(score) {}
void display ()
{
cout.setf(ios::left);
cout << setw(3) << score << name << endl;
}
private:
string name; int score;
};
//-----------------------------------------------------
// comperation function for sorting
bool operator < ( const ID& a, const ID& b )
{
Copyright: anatoliyurb Edited by snowman
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return a.score < b.score;
}
//-----------------------------------------------------
typedef deque<ID> Deque; // new name for existing datatype
int main ()
{
Deque d;
Deque::iterator Iter;
d.push_back(ID("Smith A",96));
d.push_back(ID("Amstrong B.",91));
d.push_back(ID("Watson D.",82));
for ( Iter = d.begin(); Iter != d.end(); Iter++ )
Iter->display();
sort(d.begin(),d.end()); // sort algorithm
cout << endl << "Sorted by Score" << endl;
cout << "===============" << endl;
for ( Iter = d.begin(); Iter != d.end(); Iter++ )
Iter->display();
cout << endl << "Reverse output" << endl;
cout << "===============" << endl;
Deque::reverse_iterator r = d. rbegin();
while ( r != d. rend() )
cout << r->display();
cout << endl;
return 0;
}
OUTPUT:
// 96 Smith A.
// 91 Amstrong B.
// 82 Watson D.
//
// Sorted by Score
// ===============
// 82 Watson D.
// 91 Amstrong B.
// 96 Smith A.
//
// Reverse output
// ===============
// 96 Smith A.
// 91 Amstrong B.
Copyright: anatoliyurb Edited by snowman
- 35 -
// 82 Watson D.
resize
#include <iostream>
#include <deque>
#include <algorithm>
#include <iterator>
using namespace std;
int main ()
{
deque<int> d(5);
for ( int i=0; i<5; i++ )
d[i] = i*2;
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
d. resize(7,100);
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
d. resize(4);
copy(d.begin(),d.end(),
ostream_iterator<int>(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 0 2 4 6 8
// 0 2 4 6 8 100 100
// 0 2 4 6
size
#include <iostream>
#include <deque>
#include <algorithm>
#include <iterator>
Copyright: anatoliyurb Edited by snowman
- 36 -
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
deque<char> d(5);
Print<char> print;
cout << "Size of d = " << d. size e() << endl;
fill(d.begin(),d.end(),‘*‘);
for_each(d.begin(),d.end(),print);
cout << endl;
for ( int i=0; i < d. size(); i++ )
cout << d[i] << " ";
cout << endl;
for ( int i=0; i<5; i++ )
{
cout << "Size of d = ";
for_each(d.begin(),d.end(),print);
cout << endl;
d.pop_back();
}
return 0;
}
OUTPUT:
// Size of d = 5
// * * * * *
// * * * * *
// Size of d = * * * * *
// Size of d = * * * *
// Size of d = * * *
// Size of d = * *
// Size of d = *
Copyright: anatoliyurb Edited by snowman
- 37 -
swap
#include <iostream>
#include <deque>
#include <algorithm>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//=============================
int main ()
{
int ary[] = {1,2,3,4,5,6,7,8,9,10};
Print print;
deque<int> d1(ary,ary+7);
deque<int> d2(ary+7,ary+10);
cout << "Deque d1 : ";
for_each(d1.begin(),d1.end(),print);
cout << endl;
cout << "Size of d1 = " << d1.size()
<< endl << endl;
cout << "Deque d2 : ";
for_each(d2.begin(),d2.end(),print);
cout << endl;
cout << "Size of d2 = " << d2.size()
<< endl << endl;
d1. swap(d2);
cout << "After swapping:" << endl;
cout << "Deque d1 : ";
for_each(d1.begin(),d1.end(),print);
cout << endl;
cout << "Size of d1 = " << d1.size()
<< endl << endl;
cout << "Deque d2 : ";
for_each(d2.begin(),d2.end(),print);
Copyright: anatoliyurb Edited by snowman
- 38 -
cout << endl;
cout << "Size of d2 = " << d2.size()
<< endl << endl;
return 0;
}
OUTPUT:
// Deque d1 : 1 2 3 4 5 6 7
// Size of d1 = 7
//
// Deque d2 : 8 9 10
// Size of d2 = 3
//
// After swapping:
// Deque d1 : 8 9 10
// Size of d1 = 3
//
// Deque d2 : 1 2 3 4 5 6 7
// Size of d2 = 7
list
assign
// assign a sequence to the list
#include <iostream>
#include <list>
#include <algorithm>
#include <iterator>
using namespace std;
int main ()
{
Copyright: anatoliyurb Edited by snowman
- 39 -
int ary[]={1,2,3,4,5};
list<int> l;
// assign to l the contains of ary
l. assign(ary,ary+5);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
// replace l for 3 copies of 100
l. assign(3,100);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 100 100 100
back
// returns the last element
#include <iostream>
#include <list>
#include <algorithm>
#include <string>
#include <iterator>
using namespace std;
template<class T, class D>
class Member
{
public:
Member(T t, D d) : name(t), sal(d) {}
void print();
private:
T name;
Copyright: anatoliyurb Edited by snowman
- 40 -
D sal;
};
template<class T, class D>
void Member<T,D>::print()
{
cout << name << " " << sal << endl;
}
//--------------------------------------
int main ()
{
typedef Member<string,double> M;
list<M> l;
l.push_back(M("Robert",60000));
l.push_back(M("Linda",75000));
list<M>::iterator It = l.begin();
cout << "Entire list:" << endl;
while ( It != l.end() )
(It++)->print();
cout << endl;
cout << "Return from back()" << endl;
l. back().print();
return 0;
}
OUTPUT:
// Entire list:
// Robert 60000
// Linda 75000
//
// Return from back()
// Linda 75000
begin
// returns an iterator to the beginning
#include <iostream>
#include <list>
#include <algorithm>
#include <iterator>
Copyright: anatoliyurb Edited by snowman
- 41 -
#include <numeric>
using namespace std;
int main ()
{
list<int> l(5);
iota(l. begin(),l.end(),1);
list<int>::iterator It = l. begin();
while ( It != l.end() )
cout << *It++ << " ";
cout << endl;
// third element of the list
It = l. begin()+2;
cout << *It << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 3
clear
// removes all elements
#include <iostream>
#include <list>
using namespace std;
int main ()
{
list<int> l(5,10);
cout << "Size of list = "
<< l.size() << endl;
l. clear();
cout << "After l.clear() size of list = "
<< l.size() << endl;
return 0;
}
Copyright: anatoliyurb Edited by snowman
- 42 -
OUTPUT:
// Size of list = 5
// After l.clear() size of list = 0
empty
// true if the list is empty
#include <iostream>
#include <list>
using namespace std;
int main ()
{
list<int> l;
cout << "List is ";
l. empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
l.push_back(100);
cout << "List is ";
l. empty() ? cout << "" : cout << "not ";
cout << "empty" << endl;
return 0;
}
OUTPUT:
// List is empty
// List is not empty
end
// returns an iterator to the end
#include <iostream>
#include <list>
#include <numeric>
using namespace std;
int main ()
Copyright: anatoliyurb Edited by snowman
- 43 -
{
list<int> li(10);
iota(li.begin(),li. end(),1);
list<int>::iterator It = li.begin();
while ( It != li. end() )
cout << *(It++) << " ";
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
erase
// erase an elemen
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
using namespace std;
template <class T>
void print (list<T>& l)
{
list<int>::iterator It = l.begin();
while ( It != l.end() )
{
cout << *(It++) << " ";
}
cout << endl;
}
//=====================
int main ()
{
list<int> li(10);
iota(li.begin(),li.end(),1);
print(li);
list<int>::iterator It;
Copyright: anatoliyurb Edited by snowman
- 44 -
It = find(li.begin(),li.end(),6);
// erase at the pos It
li. erase(It);
print(li);
It = find(li.begin(),li.end(),4);
// erase from beginning to the pos It
li. erase(li.begin(),It);
print(li);
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
// 1 2 3 4 5 7 8 9 10
// 4 5 7 8 9 10
front
// returns the first element
#include <iostream>
#include <list>
int main ()
{
int ary[] = {1,2,3,4,5};
list li;
for ( int i=0; i<5; i++ )
{
li.push_front(ary[i]);
cout << "front() : "
<< li. front() << endl;
}
return 0;
}
OUTPUT:
// front() : 1
// front() : 2
Copyright: anatoliyurb Edited by snowman
- 45 -
// front() : 3
// front() : 4
// front() : 5
insert
// insert elements into the list
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
using namespace std;
template <class T>
void print (list<T>& l)
{
list<int>::iterator It = l.begin();
while ( It != l.end() )
{
cout << *(It++) << " ";
}
cout << endl;
}
//====================================
int main ()
{
list<int> li1(10,0);
list<int> li2(5);
list<int>::iterator It;
iota(li2.begin(),li2.end(),1);
cout << "li1 : ";
print(li1);
cout << "li2 : ";
print(li2);
It = li1.begin();
// value of 20 at the pos It
li1. insert(++It,20);
cout << "li1 : ";
print(li1);
Copyright: anatoliyurb Edited by snowman
- 46 -
// two value of 25 at the beginning
li1. insert(li1.begin(),2,25);
cout << "li1 : ";
print(li1);
// contents of li2 at the end of li1
li1. insert t(li1.end(),li2.begin(),li2.end());
cout << "li1 : ";
print(li1);
return 0;
}
OUTPUT:
// li1 : 0 0 0 0 0 0 0 0 0 0
// li2 : 1 2 3 4 5
// li1 : 0 20 0 0 0 0 0 0 0 0 0
// li1 : 25 25 0 20 0 0 0 0 0 0 0 0 0
// li1 : 25 25 0 20 0 0 0 0 0 0 0 0 0 1 2 3 4 5
max_size
// returns the maximum number of elements the list can hold
#include <iostream>
#include <list>
int main ()
{
list li(10);
cout << "size() of li = "
<< li.size() << endl;
cout << "max_size = "
<< li. max_size() << endl;
return 0;
}
OUTPUT:
// size() of li = 10
// max_size = 4294967295
merge
Copyright: anatoliyurb Edited by snowman
- 47 -
// merge two lists
#include <iostream>
#include <list>
#include <algorithm>
#include <iterator>
using namespace std;
int main ()
{
int ary[] = {2,5,9,7,2,7,6,5};
list<int> list1(ary,ary+4);
list<int> list2(ary+4,ary+8);
cout << "list1 : ";
copy(list1.begin(),list1.end(),
ostream_iterator<int>(cout," "));
cout << endl;
cout << "list2 : ";
copy(list2.begin(),list2.end(),
ostream_iterator<int>(cout," "));
cout << endl << endl;
// you have to sort data before megring it
list1.sort();
list2.sort();
list1. merge(list2);
cout << "After \"list1.merge(list2)\" :" << endl;
cout << "list1 : ";
copy(list1.begin(),list1.end(),
ostream_iterator(cout," "));
cout << endl;
cout << "size of list2 = " << list2.size()
<< endl;
cout << "list2 is " << (list2.empty() ? "" : "not ")
<< "empty" << endl;
return 0;
}
OUTPUT:
// list1 : 2 5 9 7
Copyright: anatoliyurb Edited by snowman
- 48 -
// list2 : 2 7 6 5
//
// After "list1.merge(list2)" :
// list1 : 2 2 5 5 6 7 7 9
// size of list2 = 0
// list2 is empty
pop_back
// removes the last element
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
using namespace std;
int main ()
{
list<int> l(5);
iota(l.begin(),l.end(),1);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
while ( !l.empty() )
{
l. pop_back();
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
}
return 0;
}
OUTPUT:
// 1 2 3 4 5
// 1 2 3 4
// 1 2 3
// 1 2
// 1
Copyright: anatoliyurb Edited by snowman
- 49 -
pop_front
// removes the first element
#include <iostream>
#include <list>
#include <algorithm>
int main ()
{
list<int> l(5,0);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
cout << "Size of list = "
<< l.size() << endl;
int size = l.size();
while ( !l.empty() )
{
l. pop_front();
cout << "Size of list = "
<< l.size() << endl;
}
return 0;
}
OUTPUT:
// 0 0 0 0 0
// Size of list = 5
// Size of list = 4
// Size of list = 3
// Size of list = 2
// Size of list = 1
// Size of list = 0
push_back
// add an element to the end of the list
Copyright: anatoliyurb Edited by snowman
- 50 -
#include <iostream>
#include <list>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Name
{
public:
Name(T f, T l) : first(f), last(l) {}
void print()
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
};
//==========================================
int main ()
{
typedef Name<string> N;
typedef list<N> L;
L l;
L::iterator It;
N n1(string("Albert"),string("Johnson"));
N n2("Lana","Vinokur");
l. push_back(n1);
l. push_back(n2);
// unnamed object
l. push_back(N("Linda","Bain"));
It = l.begin();
while ( It != l.end() )
(It++)->print();
cout << endl;
return 0;
Copyright: anatoliyurb Edited by snowman
- 51 -
}
OUTPUT:
// Albert Johnson
// Lana Vinokur
// Linda Bain
push_front
// add an element to the front of the list
#include <iostream>
#include <list>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Name
{
public:
Name(T f, T l) : first(f), last(l) {}
void print()
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
};
//==========================================
int main ()
{
typedef Name<string> N;
typedef list<N> L;
L l;
L::iterator It;
N n1(string("Albert"),string("Johnson"));
N n2("Lana","Vinokur");
l. push_front(n1);
Copyright: anatoliyurb Edited by snowman
- 52 -
l. push_front(n2);
// unnamed object
l. push_front(N("Linda","Bain"));
It = l.begin();
while ( It != l.end() )
(It++)->print();
cout << endl;
return 0;
}
OUTPUT:
// Linda Bain
// Lana Vinokur
// Albert Johnson
rbegin
// returns a reverse iterator to the beginning of the list
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
#include <iterator>
using namespace std;
int main ()
{
list<int> l(10);
iota(l.begin(),l.end(),1);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
list<int>::reverse_iterator It = l. rbegin();
while ( It != l.rend() )
cout << *(It++) << " ";
cout << endl;
return 0;
Copyright: anatoliyurb Edited by snowman
- 53 -
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
// 10 9 8 7 6 5 4 3 2 1
remove
// removes elements from the list
#include <iostream>
#include <list>
#include <algorithm>
#include <string>
using namespace std;
template <class T, class D>
class Salary
{
public:
Salary(T t) : id(t) {}
Salary(T t,D d) : id(t), sal(d) {}
void print ()
{ cout << id << " " << sal << endl; }
private:
T id;
D sal;
friend bool operator ==
(const Salary& s1,const Salary& s2)
{ return s1.id == s2.id; }
};
//==========================================
int main ()
{
typedef Salary<string,double> S;
typedef list<S> L;
L l;
l.push_back(S("012345",70000.0));
l.push_back(S("012346",60000.0));
l.push_back(S("012347",72000.0));
L::iterator It = l.begin();
while ( It != l.end() )
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(It++)->print();
cout << endl;
S s("012345");
l. remove(s);
It = l.begin();
while ( It != l.end() )
(It++)->print();
cout << endl;
return 0;
}
OUTPUT:
// 012345 70000
// 012346 60000
// 012347 72000
//
// 012346 60000
// 012347 72000
remove_if
// removes elements conditionally
#include <iostream>
#include <list>
#include <algorithm>
OUTPUT:
rend
// returns a reverse iterator to the start of the list
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
#include <iterator>
using namespace std;
int main ()
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{
list<int> l(10);
iota(l.begin(),l.end(),1);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
list<int>::reverse_iterator It = l.rbegin();
while ( It != l.r r end() )
cout << *(It++) << " ";
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
// 10 9 8 7 6 5 4 3 2 1
resize
// change the size of the list
#include <iostream>
#include <list>
int main ()
{
list<int> l(10);
cout << "Size of list l = "
<< l.size();
l. resize(100);
cout << "After l.resize(100)" << endl;
cout << "Size of list l = "
<< l.size();
l. resize(5);
cout << "After l.resize(5)" << endl;
cout << "Size of list l = "
<< l.size();
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return 0;
}
OUTPUT:
// Size of list l = 10After l.resize(100)
// Size of list l = 100After l.resize(5)
// Size of list l = 5
reverse
// reverse the list
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
using namespace std;
int main ()
{
list<int> l(10);
iota(l.begin(),l.end(),1);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
l. reverse();
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8 9 10
// 10 9 8 7 6 5 4 3 2 1
size
// the number the elements in the list
#include <iostream>
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#include <list>
#include <algorithm>
int main ()
{
list<int> l(5,0);
copy(l.begin(),l.end(),
ostream_iterator<int>(cout," "));
cout << endl;
cout << "Size of list = "
<< l. size() << endl;
int size = l. size();
for ( int i=0; i<size; i++ )
// or while ( !l.empty() ) - safer
{
l.pop_front();
cout << "Size of list = "
<< l. size() << endl;
}
return 0;
}
OUTPUT:
// 0 0 0 0 0
// Size of list = 5
// Size of list = 4
// Size of list = 3
// Size of list = 2
// Size of list = 1
// Size of list = 0
sort 1.
// sorts the list
#include <iostream>
#include <list>
#include <algorithm>
#include <functional>
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using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
cout << t << " ";
}
};
//-----------------------------
int main ()
{
int ary[] = {3,2,5,7,3,6,7,2,4,5};
list<int> li(ary,ary+10);
Print<int> print;
cout << "Before sorting\nli : ";
for_each(li.begin(),li.end(),print);
cout << endl << endl;
li. sort(greater<int>());
cout << "After li.sort(greater())\nli : ";
for_each(li.begin(),li.end(),print);
cout << endl << endl;
li. sort(less<int>());
cout << "After li.sort(less())\nli : ";
for_each(li.begin(),li.end(),print);
cout << endl;
return 0;
}
OUTPUT:
// Before sorting
// li : 3 2 5 7 3 6 7 2 4 5
//
// After li.sort(greater<int>())
// li : 7 7 6 5 5 4 3 3 2 2
//
// After li.sort(less<int>())
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// li : 2 2 3 3 4 5 5 6 7 7
sort 2.
// sorts with user datatype
#include <iostream>
#include <iomanip>
#include <list>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T f, T l) :
first_n(f), last_n(l) {}
void print();
private:
string last_n, first_n;
// for sort() list member function
friend bool operator < (Member& m1,
Member& m2)
{ return m1.last_n < m2.last_n; }
};
//---------------------------------------
template <class T>
void Member<T>::print()
{
cout.setf(ios::left);
cout << setw(15) << last_n.c_str()
<< first_n << endl;
}
typedef Member<string> M;
//========================================
int main ()
{
list<M> li;
li.push_back(M("Linda","Smith"));
li.push_back(M("Frost","Robert"));
li.push_back(M("Alex","Amstrong"));
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cout << "Before sorting by last name:\n"
<< "============================"
<< endl;
list<M>::iterator It = li.begin();
while ( It != li.end() )
{
(It++)->print();
}
cout << endl;
li. sort();
cout << "After sorting by last name:\n"
<< "============================"
<< endl;
It = li.begin();
while ( It != li.end() )
{
(It++)->print();
}
return 0;
}
OUTPUT:
// Before sorting by last name:
// ============================
// Smith Linda
// Robert Frost
// Amstrong Alex
//
// After sorting by last name:
// ============================
// Amstrong Alex
// Robert Frost
// Smith Linda
splice
// merge two lists
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#include <iostream>
#include <list>
#include <algorithm>
#include <iterator>
using namespace std;
template <class T>
class Print
{
public:
void operator () (T& t)
{
cout << t << " ";
}
};
//====================================
int main ()
{
ist<int> li1, li2, li3, li4;
Print print;
for ( int i=0; i<5; i++ )
{
li1.push_back(i);
li2.push_back(i+5);
li3.push_back(i+10);
li4.push_back(i+15);
}
cout << "li1 : ";
for_each(li1.begin(),li1.end(),print);
cout << endl;
cout << "li2 : ";
for_each(li2.begin(),li2.end(),print);
cout << endl;
cout << "li3 : ";
for_each(li3.begin(),li3.end(),print);
cout << endl;
cout << "li4 : ";
for_each(li4.begin(),li4.end(),print);
cout << endl << endl;
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li1. splice(li1.end(),li2);
cout << "li1 : ";
for_each(li1.begin(),li1.end(),print);
cout << endl << endl;
li1. splice(li1.end(),li3,li3.begin(),li3.end());
cout << "li1 : ";
for_each(li1.begin(),li1.end(),print);
cout << endl << endl;
list<int>::iterator It;
It = find(li4.begin(),li4.end(),18);
li1. splice(li1.begin(),li4,It);
cout << "li1 : ";
for_each(li1.begin(),li1.end(),print);
cout << endl;
cout << "li4 : ";
for_each(li4.begin(),li4.end(),print);
cout << endl;
return 0;
}
OUTPUT:
// li1 : 0 1 2 3 4
// li2 : 5 6 7 8 9
// li3 : 10 11 12 13 14
// li4 : 15 16 17 18 19
//
// li1 : 0 1 2 3 4 5 6 7 8 9
//
// li1 : 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
//
// li1 : 18 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
// li4 : 15 16 17 19
swap
Copyright: anatoliyurb Edited by snowman
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// exchange two lists
#include <iostream>
#include <list>
#include <algorithm>
#include <numeric>
using namespace std;
void print (list<int>& l)
{
list<int>::iterator It = l.begin();
while ( It != l.end() )
{
cout << *(It++) << " ";
}
cout << endl;
}
//===============================
int main ()
{
list<int> li1(5), li2(5);
iota(li1.begin(),li1.end(),1);
iota(li2.begin(),li2.end(),5);
cout << "li1 : ";
print(li1);
cout << "li2 : ";
print(li2);
li1. swap(li2);
cout << endl <<"After swapping:" << endl;
cout << "li1 : ";
print(li1);
cout << "li2 : ";
print(li2);
return 0;
}
OUTPUT:
// li1 : 1 2 3 4 5
// li2 : 5 6 7 8 9
//
// After swapping:
// li1 : 5 6 7 8 9
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// li2 : 1 2 3 4 5
unique
// removes duplicate elements
#include <iostream>
#include <list>
#include <algorithm>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T f, T l) :
first_n(f), last_n(l) {}
void print();
private:
string last_n, first_n;
// for sort function
friend bool operator < (Member& m1,
Member& m2)
{ return m1.last_n < m2.last_n; }
// for merge and unique functions
friend bool operator == (Member& m1,
Member& m2)
{ return m1.last_n == m2.last_n; }
};
//---------------------------------------
template <class T>
void Member<T>::print()
{
cout.setf(ios::left);
cout << setw(15) << last_n.c_str()
<< first_n << endl;
}
typedef Member<string> M;
//========================================
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int main ()
{
list<M> li1;
li1.push_back(M("Linda","Smith"));
li1.push_back(M("Robert","Frost"));
li1.push_back(M("Alex","Amstrong"));
list li2;
li2.push_back(M("Linda","Smith"));
li2.push_back(M("John","Wood"));
li2.push_back(M("Alex","Amstrong"));
li1. sort();
li2. sort();
li1. merge(li2);
cout << "li1 after sorting and mergin"
<< endl;
list<M>::iterator It = li1.begin();
while ( It != li1.end() )
{
(It++)->print();
}
cout << endl;
li1. unique();
cout << "After li1.unique()" << endl;
It = li1.begin();
while ( It != li1.end() )
{
(It++)->print();
}
cout << endl;
return 0;
}
OUTPUT:
// li1 after sorting and mergin
// Amstrong Alex
// Amstrong Alex
// Frost Robert
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// Smith Linda
// Smith Linda
// Wood John
//
// After li1.unique()
// Amstrong Alex
// Frost Robert
// Smith Linda
// Wood John
set
constructors
default preicate is less
#include <iostream>
#include <set>
int main ()
{
int ary[] = { 5,3,7,5,2,3,7,5,5,4 };
set<int> s1;
set<int, greater<int> > s2;
for ( int i=0; i<sizeof(ary)/sizeof(int); i++ )
{
s1.insert(ary[i]);
s2.insert(ary[i]);
}
set<int>::iterator It = s1.begin();
cout << "s1 : ";
while ( It != s1.end() )
cout << *(It++) << " ";
cout << endl;
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It = s2.begin();
cout << "s2 : ";
while ( It != s2.end() )
cout << *(It++) << " ";
cout << endl;
// second form of constructor
set<int> s3(ary,ary+3);
It = s3.begin();
cout << "s3 : ";
while ( It != s3.end() )
cout << *(It++) << " ";
cout << endl;
// copy constructor (predicate of s1 is important)
set<int, less > s4(s1);
It = s4.begin();
cout << "s4 : ";
while ( It != s4.end() )
cout << *(It++) << " ";
cout << endl;
return 0;
}
OUTPUT:
// s1 : 2 3 4 5 7
// s2 : 7 5 4 3 2
// s3 : 3 5 7
// s4 : 2 3 4 5 7
begin
returns an iterator to the first element
#include <iostream>
#include <set>
using namespace std;
int main ()
{
int ary[] = {1,2,3,2,4,5,7,2,6,8};
set<int> s(ary,ary+10);
copy(s. beg in(),s.end(),
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ostream_iterator<int>(cout," "));
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 7 8
clear
removes all elements
#include <iostream>
#include <set>
using namespace std;
void print (set<int, less<int> >& s)
{
set<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
s. clear();
cout << "Size of set s = " << s.size() << endl;
print(s);
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 8
// Size of set s = 0
count
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returns the number of elements
#include <iostream>
#include <set>
using namespace std;
void print (set<int, less<int> >& s)
{
set<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
cout << "count of ‘2‘ (0 or 1) is ";
int n = s. count(2);
cout << n << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 8
// count of ‘2‘ (0 or 1) is 1
empty
true if the set is empty
#include <iostream>
#include <set>
using namespace std;
void print (set<int, less<int> >& s)
{
set<int, less<int> >::iterator It;
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for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
cout << "set is " << ((s. empty()) ? "" : "not ")
<< "empty" << endl;
s.clear();
cout << "set is " << ((s. empty()) ? "" : "not ")
<< "empty" << endl;
return 0;
}
OUTPUT:
// 1 2 3 4 5 6 8
// set is not empty
// set is empty
end
returns an iterator to the last element
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
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{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
typedef set<M, less<M> > S;
M m("Frost","Robert");
S s;
s.insert(m);
s.insert(M("Smith","John"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
S::iterator It = s.begin();
while ( It != s. end() )
(It++)->print();
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Robert Frost
// John Smith
equal_ranges
Copyright: anatoliyurb Edited by snowman
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returns iterators to the first and last elements that
match a certain key
#include <iostream>
#include <set>
using namespace std;
int main ()
{
set<int> c;
c.insert(1);
c.insert(2);
c.insert(4);
c.insert(10);
c.insert(11);
cout << "lower_bound(3): "
<< *c.lower_bound(3) << endl;
cout << "upper_bound(3): "
<< *c.upper_bound(3) << endl;
cout << "equal_range(3): "
<< *c. equal_range(3).first << " "
<< *c. equal_range(3).second << endl;
cout << endl;
cout << "lower_bound(5): "
<< *c.lower_bound(5) << endl;
cout << "upper_bound(5): "
<< *c.upper_bound(5) << endl;
cout << "equal_range(5): "
<< *c. equal_range(5).first << " "
<< *c. equal_range(5).second << endl;
cin.get();
}
OUTPUT:
// lower_bound(3): 4
// upper_bound(3): 4
// equal_range(3): 4 4
//
// lower_bound(5): 10
// upper_bound(5): 10
// equal_range(5): 10 10
Copyright: anatoliyurb Edited by snowman
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erase
removes elements
#include <iostream>
#include <set>
using namespace std;
void print (set<int, less<int> >& s)
{
set<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
// erase ‘2‘
s. erase(2);
print(s);
set<int, less<int> >::iterator It;
It = s.find(5);
// erase ‘5‘
s. erase(It);
print(s);
It = s.find(4);
// erase from It to the end of set
s. erase(It,s.end());
print(s);
return 0;
Copyright: anatoliyurb Edited by snowman
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}
OUTPUT:
// 1 2 3 4 5 6 8
// 1 3 4 5 6 8
// 1 3 4 6 8
// 1 3
find
finds a given element
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
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typedef set<M, less<M> > S;
M m("Frost","Robert");
S s;
s.insert(m);
s.insert(M("Smith","John"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
S::iterator It = s.begin();
while ( It != s.end() )
(It++)->print();
It = s. find(m);
if ( It == s.end() )
cout << "element not found" << endl;
else
{
cout << "element is found : ";
(*It).print();
}
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Robert Frost
// John Smith
// element is found : Robert Frost
insert
inserts elements into the set
#include <iostream>
#include <set>
using namespace std;
void print (set<int, less<int> >& s)
{
set<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
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cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s. insert(10);
print(s);
s. insert(ary,ary+5);
print(s);
set<int, less<int> >::iterator It = s.begin();
s. insert(It,20);
print(s);
return 0;
}
OUTPUT:
// 10
// 1 2 3 10
// 1 2 3 10 20
lower_bound
returns an iterator to the first element greater
than a certain value
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l) : last(l), first("") {} // for upper_bound
// and lower_bound
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Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
typedef set<M, less<M> > S;
S s;
s.insert(M("Smith","John"));
s.insert(M("Shevchenko","Taras"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
s.insert(M("Pushkin","Alexander"));
s.insert(M("Pasternak","Biris"));
S::iterator It = s.begin();
while ( It != s.end() )
(It++)->print();
cout << endl;
M m1("P");
M m2("Pzz");
S::iterator low = s. lower_bound(m1);
S::iterator upp = s.upper_bound(m2);
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It = low;
while ( It != upp )
(It++)->print();
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Biris Pasternak
// Alexander Pushkin
// Taras Shevchenko
// John Smith
//
// Biris Pasternak
// Alexander Pushkin
key_comp
returns the function that compares keys
#include <iostream>
#include <set>
using namespace std ;
template
void truefalse(T t)
{
cout << (t?"True":"False") << endl;
}
int main ()
{
set<int> s;
cout << "s.key_comp()(1,2) returned ";
truefalse(s. key_comp()(1,2)); // True
cout << "s.key_comp()(2,1) returned ";
truefalse(s. key_comp()(2,1)); // False
cout << "s.key_comp()(1,1) returned ";
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truefalse(s. key_comp()(1,1)); // False
return 0;
}
OUTPUT:
// s.key_comp()(1,2) returned True
// s.key_comp()(2,1) returned False
// s.key_comp()(1,1) returned False
max_size
the maximum number of elements that the set can hold
#include <iostream>
#include <set>
#include <algorithm>
using namespace std;
void print (set<int, less<int> >& s)
{
copy(s.begin(),s.end(),
ostream_iterator<int>(cout," "));
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
cout << "size of set ‘s‘ = "
<< s.size() << endl;
cout << "max_size of ‘s‘ = "
<< s. max_size() << endl;
return 0;
}
OUTPUT:
Copyright: anatoliyurb Edited by snowman
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// 1 2 3 4 5 6 8
// size of set ‘s‘ = 7
// max_size of ‘s‘ = 4294967295
rbegin
returns a reverse iterator to the end of the set
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
typedef set<M, less<M> > S;
M m("Frost","Robert");
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S s;
s.insert(m);
s.insert(M("Smith","John"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
S::iterator It = s.begin();
while ( It != s.end() )
(It++)->print();
cout << endl;
S::reverse_iterator rI = s. rbegin();
while ( rI != s.rend() )
(rI++)->print();
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Robert Frost
// John Smith
//
// John Smith
// Robert Frost
// Linda Bain
// Bill Amstrong
rend
returns a reverse iterator to the beginning of the set
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
Copyright: anatoliyurb Edited by snowman
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public:
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
typedef set<M, less<M> > S;
M m("Frost","Robert");
S s;
s.insert(m);
s.insert(M("Smith","John"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
S::iterator It = s.begin();
while ( It != s.end() )
(It++)->print();
cout << endl;
S::reverse_iterator rI = s.rbegin();
while ( rI != s. rend() )
(rI++)->print();
return 0;
Copyright: anatoliyurb Edited by snowman
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}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Robert Frost
// John Smith
//
// John Smith
// Robert Frost
// Linda Bain
// Bill Amstrong
size
the number of elements in the set
#include <iostream>
#include <set>
using namespace std;
void print (set<int, less<int> >& s)
{
set<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
set<int, less<int> > s;
s.insert(ary,ary+10);
cout << "Size of set s = " << s. size() << endl;
print(s);
s.clear();
cout << "Size of set s = " << s. size() << endl;
return 0;
}
OU TPUT:
// Size of set s = 7
Copyright: anatoliyurb Edited by snowman
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// 1 2 3 4 5 6 8
// Size of set s = 0
swap
exchanges two sets
#include <iostream>
#include <set>
#include <algorithm>
using namespace std;
void print (set<int, less<int> >& s)
{
copy(s.begin(),s.end(),
ostream_iterator<int>(cout," "));
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary1[] = {1,2,3,2,3,4,8,2,5,6};
int ary2[] = {5,0,9,2,3,4,8,2,5,6};
set<int, less<int> > s1, s2;
s1.insert(ary1,ary1+10);
cout << "s1 : ";
print(s1);
cout << "s2 : ";
s2.insert(ary2,ary2+10);
print(s2);
if ( s1 != s2 )
s1. swap(s2);
cout << "s1 : ";
print(s1);
cout << "s2 : ";
print(s2);
return 0;
Copyright: anatoliyurb Edited by snowman
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}
OUTPUT: :
// s1 : 1 2 3 4 5 6 8
// s2 : 0 2 3 4 5 6 8 9
// s1 : 0 2 3 4 5 6 8 9
// s2 : 1 2 3 4 5 6 8
upper_bound
returns an iterator to the first element greater than
a certain value
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l) : last(l), first("") {} // for upper_bound
// and lower_bound
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
Copyright: anatoliyurb Edited by snowman
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//===============================================
int main ()
{
typedef Member<string> M;
typedef set<M, less<M> > S;
S s;
s.insert(M("Smith","John"));
s.insert(M("Shevchenko","Taras"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
s.insert(M("Pushkin","Alexander"));
s.insert(M("Pasternak","Boris"));
S::iterator It = s.begin();
while ( It != s.end() )
(It++)->print();
cout << endl;
M m1("P");
M m2("Pzz");
S::iterator low = s.lower_bound(m1);
S::iterator upp = s. upper_bound(m2);
It = low;
while ( It != upp )
(It++)->print();
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Biris Pasternak
// Alexander Pushkin
// Taras Shevchenko
// John Smith
//
// Boris Pasternak
// Alexander Pushkin
Copyright: anatoliyurb Edited by snowman
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value_comp
returns the function that compares values
#include <iostream>
#include <set>
using namespace std ;
template
void truefalse(T t)
{
cout << (t?"True":"False") << endl;
}
int main ()
{
set<int> s;
cout << "s.value_comp()(1,2) returned ";
truefalse(s. value_comp()(1,2)); // True
cout << "s.value_comp()(2,1) returned ";
truefalse(s. value_comp()(2,1)); // False
cout << "s.value_comp()(1,1) returned ";
truefalse(s. value_comp()(1,1)); // False
return 0;
}
OUTPUT:
// s.value_comp()(1,2) returned True
// s.value_comp()(2,1) returned False
// s.value_comp()(1,1) returned False
Copyright: anatoliyurb Edited by snowman
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multiset
constructors
#include <iostream>
#include <set>
using namespace std;
int main ()
{
int ary[] = {1,2,3,2,5,4,2,1,4,5};
multiset<int, less<int> > ms1;
multiset<int, greater<int> > ms2(ary,ary+10);
multiset<int>::iterator It;
cout << "ms2 : ";
for ( It = ms2.begin(); It != ms2.end(); It++ )
cout << *It << " ";
cout << endl;
// copy constructor
multiset<int, greater<int> > ms3(ms2);
cout << "ms3 : ";
for ( It = ms3.begin(); It != ms3.end(); It++ )
cout << *It << " ";
cout << endl;
It = ms2.begin();
while ( It != ms2.end() )
ms1.insert(*It++);
cout << "ms1 : ";
for ( It = ms1.begin(); It != ms1.end(); It++ )
cout << *It << " ";
cout << endl;
return 0;
}
OUTPUT:
Copyright: anatoliyurb Edited by snowman
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// ms2 : 5 5 4 4 3 2 2 2 1 1
// ms3 : 5 5 4 4 3 2 2 2 1 1
// ms1 : 1 1 2 2 2 3 4 4 5 5
begin
returns an iterator to the first element
#include <iostream>
#include <set>
#include <algorithm>
using namespace std;
int main ()
{
int ary[] = {1,2,3,2,4,5,7,2,6,8};
multiset<int> s(ary,ary+10);
copy(s. begin(),s.end(),
ostream_iterator<int>(cout," "));
return 0;
}
OUTPUT:
// 1 2 2 2 3 4 5 6 7 8
clear
removes all elements
#include <iostream>
#include <set>
using namespace std;
void print (multiset<int, less<int> >& s)
{
multiset<int>::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
Copyright: anatoliyurb Edited by snowman
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int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
multiset<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
s. clear();
cout << "Size of multiset s = " << s.size() << endl;
print(s);
return 0;
}
OUTPUT:
// 1 2 2 2 3 3 4 5 6 8
// Size of multiset s = 0
count
returns the number of elements
#include <iostream>
#include <set>
using namespace std;
void print (multiset<int, less<int> >& s)
{
multiset<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
multiset<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
cout << "count of ‘2‘ is ";
Copyright: anatoliyurb Edited by snowman
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int n = s. count(2);
cout << n << endl;
return 0;
}
OUTPUT:
// 1 2 2 2 3 3 4 5 6 8
// count of ‘2‘ is 3
empty
true if the multiset is empty
#include <iostream>
#include <set>
using namespace std;
void print (multiset<int, less<int> >& s)
{
multiset<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
multiset<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
cout << "multiset is " << ((s. empty()) ? "" : "not ")
<< "empty" << endl;
s.clear();
cout << "multiset is " << ((s. empty()) ? "" : "not ")
<< "empty" << endl;
return 0;
Copyright: anatoliyurb Edited by snowman
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}
OUTPUT:
// 1 2 2 2 3 3 4 5 6 8
// multiset is not empty
// multiset is empty
end
returns an iterator to the last element
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
Copyright: anatoliyurb Edited by snowman
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typedef multiset<M, less<M> > S;
M m("Frost","Robert");
S s;
s.insert(m);
s.insert(M("Smith","John"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
S::iterator It = s.begin();
while ( It != s. end() )
(It++)->print();
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Robert Frost
// John Smith
equal_ranges
returns iterators to the first and last elements that
match a certain key
#include <iostream>
#include <set>
OUTPUT:
erase
removes elements
#include <iostream>
#include <set>
using namespace std;
void print (multiset<int, less<int> >& s)
{
multiset<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
Copyright: anatoliyurb Edited by snowman
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cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
multiset<int, less<int> > s;
s.insert(ary,ary+10);
print(s);
// erase all ‘2‘
s. erase(2);
print(s);
multiset<int, less<int> >::iterator It;
It = s.find(5);
// erase ‘5‘
s. erase(It);
print(s);
It = s.find(4);
// erase from It to the end of multiset
s. erase(It,s.end());
print(s);
return 0;
}
OUTPUT:
// 1 2 2 2 3 3 4 5 6 8
// 1 3 3 4 5 6 8
// 1 3 3 4 6 8
// 1 3 3
f f ind
finds a given element
#include <iostream>
Copyright: anatoliyurb Edited by snowman
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#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_str()
<< last << endl;
}
private:
T first, last;
// const !!!
friend bool operator < (const Member& m1, const Member& m2)
{
return (m1.last < m2.last) ? true : false;
}
friend bool operator == (const Member& m1, const Member& m2)
{
return (m1.last == m2.last) ? true : false;
}
};
//===============================================
int main ()
{
typedef Member<string> M;
typedef multiset<M, less<M> > S;
M m("Frost","Robert");
S s;
s.insert(m);
s.insert(M("Smith","John"));
s.insert(M("Amstrong","Bill"));
s.insert(M("Bain","Linda"));
S::iterator It = s.begin();
while ( It != s.end() )
(It++)->print();
Copyright: anatoliyurb Edited by snowman
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It = s. find(m);
if ( It == s.end() )
cout << "element not found" << endl;
else
{
cout << "element is found : ";
(*It).print();
}
return 0;
}
OUTPUT:
// Bill Amstrong
// Linda Bain
// Robert Frost
// John Smith
// element is found : Robert Frost
insert
inserts elements into the multiset
#include <iostream>
#include <set>
using namespace std;
void print (multiset<int, less<int> >& s)
{
multiset<int, less<int> >::iterator It;
for ( It = s.begin(); It != s.end(); It++ )
cout << *It << " ";
cout << endl;
}
//--------------------------------------------
int main ()
{
int ary[] = {1,2,3,2,3,4,8,2,5,6};
multiset > s;
s. insert(10);
print(s);
Copyright: anatoliyurb Edited by snowman
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s. insert(ary,ary+5);
print(s);
multiset<int, less<int> >::iterator It = s.begin();
s. insert(It,20);
print(s);
return 0;
}
OUTPUT:
// 10
// 1 2 2 3 3 10
// 1 2 2 3 3 10 20
lower_bound
returns an iterator to the first element greater
than a certain value
#include <iostream>
#include <set>
#include <iomanip>
#include <string>
using namespace std;
template <class T>
class Member
{
public:
Member(T l) : last(l), first("") {} // for upper_bound
// and lower_bound
Member(T l, T f) : last(l), first(f) {}
void print() const // const !!!
{
cout.setf(ios::left);
cout << setw(15) << first.c_
Copyright: anatoliyurb Edited by snowman
- 98 -
map
constructors
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef map<int, char, less<int> > M;
M m1;
m1.insert(M::value_type(2,‘B‘));
m1.insert(M::value_type(3,‘C‘));
m1.insert(M::value_type(1,‘A‘));
M::iterator It = m1.begin();
cout << endl << "m1:" << endl;
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
// copy constructor
M m2(m1);
It = m2.begin();
cout << endl << "m2:" << endl;
while ( It != m2.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
M m3(m2.begin(),m2.end());
Copyright: anatoliyurb Edited by snowman
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It = m3.begin();
cout << endl << "m3:" << endl;
while ( It != m3.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
return 0;
}
OUTPUT:
// m1:
// 1 - A
// 2 - B
// 3 - C
//
// m2:
// 1 - A
// 2 - B
// 3 - C
//
// m3:
// 1 - A
// 2 - B
// 3 - C
begin
returns an iterator to the first element
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef map<int, char, greater<int> > M;
typedef M::value_type v_t;
M m;
Copyright: anatoliyurb Edited by snowman
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m.insert(v_t(2,‘B‘));
m.insert(v_t(3,‘C‘));
m.insert(v_t(1,‘A‘));
M::iterator It = m. begin();
cout << "m:" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
return 0;
}
OUTPUT:
// m:
// 3 - C
// 2 - B
// 1 - A
clear
removes all elements
#include <iostream>
#include <map>
OUTPUT:
count
returns the number of elements
#include <iostream>
#include <map>
#include <list>
#include <numeric>
using namespace std;
int main ()
{
Copyright: anatoliyurb Edited by snowman
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list<int> L1(3), L2(3);
iota(L1.begin(),L1.end(),1);
iota(L2.begin(),L2.end(),4);
typedef map<int, list<int> > M;
M m;
m.insert(M::value_type(1,L1));
m.insert(M::value_type(2,L2));
M::iterator It;
list<int>::iterator Li;
for ( It = m.begin(); It != m.end(); It++ )
{
cout << "map " << (*It).first << ": ";
for ( Li = It->second.begin();
Li != It->second.end(); Li++ )
cout << *Li << " ";
cout << endl;
}
int n = m. count(2);
cout << "count of element with key ‘2‘ (0 or 1) is "
<< n << endl;
return 0;
}
OUTPUT:
// map 1: 1 2 3
// map 2: 4 5 6
// count of element with key ‘2‘ (0 or 1) is 1
empty
true if the map is empty
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef map<int,int> M;
M m;
Copyright: anatoliyurb Edited by snowman
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m[1] = 100;
m[3] = 200;
m[5] = 300;
cout << "values of map ‘m‘: ";
M::iterator It = m.begin();
while ( It != m.end() )
{
cout << (*It).second << " ";
It++;
}
cout << endl;
cout << "size of map = " << m.size()
<< endl;
cout << "map ‘m‘ is " << (m. empty() ?
"" : "not ") << "empty" << endl << endl;
m.erase(m.begin(),m.end());
cout << "After m.erase(m.begin(),m.end())"
<< endl;
cout << "size of map = " << m.size()
<< endl;
cout << "map ‘m‘ is " << (m. empty() ?
"" : "not ") << "empty" << endl;
return 0;
}
OUTPUT:
// values of map ‘m‘: 100 200 300
// size of map = 3
// map ‘m‘ is not empty
//
// After m.erase(m.begin(),m.end())
// size of map = 0
// map ‘m‘ is empty
end
returns an iterator to the last element
#include <iostream>
Copyright: anatoliyurb Edited by snowman
- 103 -
#include <map>
OUTPUT:
equal_ranges
returns iterators to the first and last elements that
match a certain key
#include <iostream>
#include <map>
OUTPUT:
erase
removes elements
#include <iostream>
#include <map>
#include <string>
using namespace std;
typedef map<string, int, less<string> > M;
void print (M& m)
{
M::iterator It = m.begin();
cout << "map :" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - ";
cout << (*It).second << endl;
It++;
}
}
//-----------------------------------
int main ()
{
typedef M::value_type v_t;
M m;
m.insert(v_t("AAA",1));
m.insert(v_t("BBB",2));
Copyright: anatoliyurb Edited by snowman
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m.insert(v_t("CCC",3));
m["DDD"] = 4;
m["EEE"] = 5;
print(m);
// remove element with key ‘BBB‘
m. erase("BBB");
print(m);
M::iterator It;
It = m.find("DDD");
// remove element pointed by It
m. erase(It);
print(m);
It = m.find("CCC");
// remove the range of elements
m. erase(m.begin(),++It);
print(m);
return 0;
}
OUTPUT:
// map :
// AAA - 1
// BBB - 2
// CCC - 3
// DDD - 4
// EEE - 5
// map :
// AAA - 1
// CCC - 3
// DDD - 4
// EEE - 5
// map :
// AAA - 1
// CCC - 3
// EEE - 5
// map :
// EEE - 5
Copyright: anatoliyurb Edited by snowman
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find
finds a given element
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef map<int,char> M;
char ch = ‘A‘;
M m;
for ( int i=0; i<5; i++ )
m[i] = ch++;
M::iterator It = m.begin();
cout << "map m:" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
It = m. find(4);
if ( It != m.end() )
cout << "element key ‘4‘ has value "
<< (*It).second << endl;
else
cout << "element key ‘4‘ not found"
<< endl;
return 0;
}
OUTPUT:
// map m:
// 0 - A
// 1 - B
// 2 - C
// 3 - D
// 4 - E
// element key ‘4‘ has value E
Copyright: anatoliyurb Edited by snowman
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insert
inserts elements into the map
#include <iostream>
#include <map>
#include <string>
using namespace std;
int main ()
{
typedef map<int, char, less<char> > M;
typedef M::value_type v_t;
M m1, m2;
char ch = ‘A‘;
for ( int i=0; i<3; i++ )
{
m1[i+1] = ch+i;
m2[i+4] = ch+i+3;
}
cout << "m1 :" << endl;
M::iterator It = m1.begin();
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
cout << "m2 :" << endl;
It = m2.begin();
while ( It != m2.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
// insert new element
Copyright: anatoliyurb Edited by snowman
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m1. insert(v_t(5,‘E‘));
It = m2.find(6);
// insert element pointed by It
m1. insert(*It);
cout << "m1 :" << endl;
It = m1.begin();
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
// insert the range of elements
m1. insert(m2.begin(),m2.end());
cout << "m1 :" << endl;
It = m1.begin();
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
return 0;
}
OUTPUT:
// m1 :
// 1 - A
// 2 - B
// 3 - C
// m2 :
// 4 - D
// 5 - E
// 6 - F
// m1 :
// 1 - A
// 2 - B
// 3 - C
// 5 - E
// 6 - F
Copyright: anatoliyurb Edited by snowman
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// m1 :
// 1 - A
// 2 - B
// 3 - C
// 4 - D
// 5 - E
// 6 - F
lower_bound
returns an iterator to the first element greater
than a certain value
#include <iostream>
#include <map>
#include <ctime>
using namespace std;
unsigned long int gener_rand()
{
unsigned long int random =
(unsigned long int)
(10000.0 * rand() /
(RAND_MAX + 1.0 )) % 10;
return random;
}
//-----------------------------------
int main ()
{
unsigned long int ary[100];
typedef map<int, unsigned long int> M;
M m;
// initialize all values to 0
for ( int i=0; i<10; i++ )
m[i] = 0;
srand(time(0));
// initialize ary[] with random values
for ( int i=0; i<100; i++ )
ary[i] = gener_rand();
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for ( int i=0; i<100; i++ )
{
if ( i % 10 == 0 && i != 0 )
cout << endl;
cout << ary[i] << " ";
// generate freaquances
m[ary[i]] += 1;
}
cout << endl << endl;
M::iterator It = m.begin();
while ( It != m.end() )
{
cout << "number " << (*It).first
<< " occurred " << (*It).second
<< " time(s)" << endl;
It++;
}
cout << endl;
m[12] = 123;
m[15] = 234;
m[18] = 345;
It = m. lo wer_bound(11);
cout << "lower_bound(11) = "
<< (*It).first << endl;
It = m.upper_bound(11);
cout << "upper_bound(11) = "
<< (*It).first << endl;
return 0;
}
OUTPUT:
// 9 7 9 6 9 6 2 0 8 9
// 6 6 6 8 0 9 5 6 5 7
// 2 1 0 3 2 3 4 4 2 2
// 2 1 9 1 8 9 8 0 0 6
// 9 6 3 6 5 3 5 0 0 0
// 8 2 2 8 6 4 2 0 9 4
// 3 1 6 2 3 4 2 1 5 2
// 8 5 8 1 1 3 5 7 4 6
// 7 2 9 0 1 5 4 4 6 4
Copyright: anatoliyurb Edited by snowman
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// 9 9 5 5 2 8 0 4 0 6
//
// number 0 occurred 12 time(s)
// number 1 occurred 8 time(s)
// number 2 occurred 14 time(s)
// number 3 occurred 7 time(s)
// number 4 occurred 10 time(s)
// number 5 occurred 10 time(s)
// number 6 occurred 14 time(s)
// number 7 occurred 4 time(s)
// number 8 occurred 9 time(s)
// number 9 occurred 12 time(s)
//
// lower_bound(11) = 12
// upper_bound(11) = 12
key_comp
returns the function that compares keys
#include <iostream>
#include <map>
OUTPUT:
max_size
the maximum number of elements that the map can hold
#include <iostream>
#include <map>
OUTPUT:
rb egin
returns a reverse iterator to the end of the map
#include <iostream>
#include <map>
#include <iomanip>
#include <string>
using namespace std;
Copyright: anatoliyurb Edited by snowman
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template<class T>
class ID
{
public:
ID(T t, T n) : id(t), name(n) {}
void print ()
{
cout.setf(ios::left);
cout << setw(15) << name.c_str()
<< id << endl;
cout.unsetf(ios::left);
}
private:
T id, name;
};
//======================================
int main ()
{
typedef ID<string> Id;
typedef map<int, Id> M;
typedef M::value_type v_t;
M m;
m.insert(v_t(1,Id("000123","Shevchenko")));
m.insert(v_t(2,Id("000124","Pushkin")));
m.insert(v_t(3,Id("000125","Shakespeare")));
// same key
m.insert(v_t(3,Id("000126","Smith")));
M::reverse_iterator It = m. rbegin();
while ( It != m.rend() )
{
cout.setf(ios::left);
cout << setw(3) << (*It).first;
It->second.print();
It++;
}
return 0;
}
O O UTPUT:
// 3 Shakespeare 000125
// 2 Pushkin 000124
Copyright: anatoliyurb Edited by snowman
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// 1 Shevchenko 000123
rend
returns a reverse iterator to the beginning of the map
#include <iostream>
#include <map>
#include <iomanip>
#include <string>
using namespace std;
template<class T>
class ID
{
public:
ID(T t, T n) : id(t), name(n) {}
void print ()
{
cout.setf(ios::left);
cout << setw(15) << name.c_str()
<< id << endl;
cout.unsetf(ios::left);
}
private:
T id, name;
};
//======================================
int main ()
{
typedef ID<string> Id;
typedef map<int, Id> M;
typedef M::value_type v_t;
M m;
m.insert(v_t(1,Id("000123","Shevchenko")));
m.insert(v_t(2,Id("000124","Pushkin")));
m.insert(v_t(3,Id("000125","Shakespeare")));
// same key
m.insert(v_t(3,Id("000126","Smith")));
M::reverse_iterator It = m.rbegin();
while ( It != m. rend() )
Copyright: anatoliyurb Edited by snowman
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{
cout.setf(ios::left);
cout << setw(3) << (*It).first;
It->second.print();
It++;
}
return 0;
}
OUTPUT:
// 3 Shakespeare 000125
// 2 Pushkin 000124
// 1 Shevchenko
multimap
constructors
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef multimap<int, char, less<int> > M;
M m1;
m1.insert(M::value_type(2,‘B‘));
m1.insert(M::value_type(3,‘C‘));
m1.insert(M::value_type(1,‘A‘));
m1.insert(M::value_type(1,‘a‘));
M::iterator It = m1.begin();
cout << endl << "m1:" << endl;
while ( It != m1.end() )
{
Copyright: anatoliyurb Edited by snowman
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cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
// copy constructor
M m2(m1);
It = m2.begin();
cout << endl << "m2:" << endl;
while ( It != m2.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
M m3(m2.begin(),m2.end());
It = m3.begin();
cout << endl << "m3:" << endl;
while ( It != m3.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
return 0;
}
OUTPUT:
// m1:
// 1 - A
// 1 - a
// 2 - B
// 3 - C
//
// m2:
// 1 - A
// 1 - a
// 2 - B
Copyright: anatoliyurb Edited by snowman
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// 3 - C
//
// m3:
// 1 - A
// 1 - a
// 2 - B
// 3 - C
begin
returns an iterator to the first element
#include <iostream>
#include <map>
#include <string>
using namespace std;
int main ()
{
typedef multimap<string,int> M;
typedef M::value_type v_t;
M m;
m.insert(v_t("first",100));
m.insert(v_t("second",200));
m.insert(v_t("third",300));
m.insert(v_t("second",400));
m.insert(v_t("third",500));
M::iterator It = m. begin();
cout << "m:" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
return 0;
}
OUTPUT:
// m:
Copyright: anatoliyurb Edited by snowman
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// first - 100
// second - 200
// second - 400
// third - 300
// third - 500
clear
removes all elements
#include <iostream>
#include <map>
OUTPUT:
count
returns the number of elements
#include <iostream>
#include <map>
#include <string>
#include <fstream>
using namespace std;
int main ()
{
typedef multimap<char,string> M1;
typedef M1::value_type v_t1;
M1 m1;
typedef multimap<string,char,less<string> > M2;
typedef M2::value_type v_t2;
M2 m2;
string word;
int counter = 0;
ifstream In("/usr/share/dict/words");
if ( In.good() )
{
while(1)
{
getline(In,word);
Copyright: anatoliyurb Edited by snowman
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char ch = word.at(0);
// file is sorted
if ( ch != ‘A‘ && ch != ‘a‘ )
break;
else
{
// for conting of words
m1.insert(v_t1(ch,word));
// for upper-lower bound
m2.insert(v_t2(word,ch));
}
counter++;
}
In.close();
}
cout << "System Dictionary consists " << counter
<< " words,\nwith first letter ‘a‘ or ‘A‘"
<< endl;
cout << m1. count(‘A‘) << " words start with ‘A‘"
<< endl;
cout << m1. count(‘a‘) << " words start with ‘a‘"
<< endl;
M2::iterator low = m2.lower_bound("Aba");
M2::iterator upp = m2.upper_bound("Abe");
cout << "Range of the words from ‘Aba‘ to ‘Abe‘:"
<< endl;
while ( low != upp )
{
cout << (*low).first << endl;
low++;
}
return 0;
}
OUTPUT:
// System Dictionary consists 3577 words,
// with first letter ‘a‘ or ‘A‘
// 491 words start with ‘A‘
// 3086 words start with ‘a‘
// Range of the words from ‘Aba‘ to ‘Abe‘:
// Ababa
// Abba
// Abbott
Copyright: anatoliyurb Edited by snowman
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// Abby
// Abe
empty
true if the maltimap is empty
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef multimap<int,int> M;
typedef M::value_type v_t;
M m;
m.insert(v_t(1,100));
m.insert(v_t(1,200));
m.insert(v_t(2,300));
m.insert(v_t(3,400));
cout << "values of multimap ‘m‘: ";
M::iterator It = m.begin();
while ( It != m.end() )
{
cout << (*It).second << " ";
It++;
}
cout << endl;
cout << "size of multimap = " << m.size()
<< endl;
cout << "multimap ‘m‘ is " << (m. empty() ?
"" : "not ") << "empty" << endl << endl;
m.erase(m.begin(),m.end());
cout << "After m.erase(m.begin(),m.end())"
<< endl;
cout << "size of multimap = " << m.size()
<< endl;
cout << "multimap ‘m‘ is " << (m. empty() ?
"" : "not ") << "empty" << endl;
Copyright: anatoliyurb Edited by snowman
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return 0;
}
OUTPUT:
// values of multimap ‘m‘: 100 200 300 400
// size of multimap = 4
// multimap ‘m‘ is not empty
//
// After m.erase(m.begin(),m.end())
// size of multimap = 0
// multimap ‘m‘ is empty
end
returns an iterator to the last element
#include <iostream>
#include <map>
#include <string>
using namespace std;
int main ()
{
typedef multimap<string,int> M;
typedef M::value_type v_t;
M m;
m.insert(v_t("first",100));
m.insert(v_t("second",200));
m.insert(v_t("third",300));
m.insert(v_t("second",400));
m.insert(v_t("third",500));
M::iterator It = m.begin();
cout << "m:" << endl;
while ( It != m. end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
Copyright: anatoliyurb Edited by snowman
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return 0;
}
OUTPUT:
// m:
// first - 100
// second - 200
// second - 400
// third - 300
// third - 500
equal_ranges
returns iterators to the first and last elements that
match a certain key
#include <iostream>
#include <map>
OUTPUT:
erase
removes elements
#include <iostream>
#include <map>
#include <string>
using namespace std;
typedef multimap<string, int, less<string> > M;
void print (M& m)
{
M::iterator It = m.begin();
cout << "multimap :" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - ";
cout << (*It).second << endl;
It++;
}
}
//-----------------------------------
Copyright: anatoliyurb Edited by snowman
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int main ()
{
typedef M::value_type v_t;
M m;
m.insert(v_t("AAA",1));
m.insert(v_t("BBB",2));
m.insert(v_t("CCC",3));
m.insert(v_t("EEE",4));
m.insert(v_t("CCC",5));
m.insert(v_t("DDD",6));
print(m);
// remove element with key ‘BBB‘
m. erase("BBB");
print(m);
M::iterator It;
It = m.find("DDD");
// remove element pointed by It
m. erase(It);
print(m);
It = m.find("CCC");
// remove the range of elements
m. erase(m.begin(),It);
print(m);
return 0;
}
OUTPUT:
// multimap :
// AAA - 1
// BBB - 2
// CCC - 3
// CCC - 5
// DDD - 6
// EEE - 4
// multimap :
// AAA - 1
// CCC - 3
// CCC - 5
// DDD - 6
Copyright: anatoliyurb Edited by snowman
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// EEE - 4
// multimap :
// AAA - 1
// CCC - 3
// CCC - 5
// EEE - 4
// multimap :
// CCC - 3
// CCC - 5
// EEE - 4
find
finds a given element
#include <iostream>
#include <map>
using namespace std;
int main ()
{
typedef multimap<int,char> M;
typedef M::value_type v_t;
char ch = ‘A‘;
M m;
for ( int i=0; i<5; i++ )
m.insert(v_t(i,ch++));
m.insert(v_t(4,‘F‘));
M::iterator It = m.begin();
cout << "multimap m:" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
It = m. find(4);
if ( It != m.end() )
cout << "element key ‘4‘ has value "
Copyright: anatoliyurb Edited by snowman
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<< (*It).second << endl;
else
cout << "element key ‘4‘ not found"
<< endl;
M::iterator upp = m.upper_bound(4);
cout << "all elements with key ‘4‘" << endl;
while ( It != upp )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
return 0;
}
OUTPUT:
// multimap m:
// 0 - A
// 1 - B
// 2 - C
// 3 - D
// 4 - E
// 4 - F
// element key ‘4‘ has value E
// all elements with key ‘4‘
// 4 - E
// 4 - F
insert
inserts elements into the maltimap
#include <iostream>
#include <map>
#include <string>
using namespace std;
int main ()
{
typedef multimap<int, char, less<char> > M;
typedef M::value_type v_t;
M m1, m2;
Copyright: anatoliyurb Edited by snowman
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char ch = ‘A‘;
for ( int i=0; i<3; i++ )
{
m1. insert(v_t(i+1,ch+i));
m2. insert(v_t(i+4,ch+i+3));
}
cout << "m1 :" << endl;
M::iterator It = m1.begin();
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
cout << "m2 :" << endl;
It = m2.begin();
while ( It != m2.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
// insert new element
m1. insert(v_t(5,‘E‘));
It = m2.find(6);
// insert element pointed by It
m1. insert(*It);
cout << "m1 :" << endl;
It = m1.begin();
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
// insert the range of elements
m1. insert(m2.begin(),m2.end());
Copyright: anatoliyurb Edited by snowman
- 125 -
cout << "m1 :" << endl;
It = m1.begin();
while ( It != m1.end() )
{
cout << (*It).first << " - "
<< (*It).second << endl;
It++;
}
return 0;
}
OUTPUT:
// m1 :
// 1 - A
// 2 - B
// 3 - C
// m2 :
// 4 - D
// 5 - E
// 6 - F
// m1 :
// 1 - A
// 2 - B
// 3 - C
// 5 - E
// 6 - F
// m1 :
// 1 - A
// 2 - B
// 3 - C
// 4 - D
// 5 - E
// 5 - E
// 6 - F
// 6 - F
lower_bound
returns an iterator to the first element greater
than a certain value
#include <iostream>
Copyright: anatoliyurb Edited by snowman
- 126 -
#include <map>
#include <string>
#include <fstream>
using namespace std;
int main ()
{
typedef multimap<char,string> M1;
typedef M1::value_type v_t1;
M1 m1;
typedef multimap<string,char,less<string> > M2;
typedef M2::value_type v_t2;
M2 m2;
string word;
int counter = 0;
ifstream In("/usr/share/dict/words");
if ( In.good() )
{
while(1)
{
getline(In,word);
char ch = word.at(0);
// file is sorted
if ( ch != ‘A‘ && ch != ‘a‘ )
break;
else
{
// for counting of words
m1.insert(v_t1(ch,word));
// for upper-lower bound
m2.insert(v_t2(word,ch));
}
counter++;
}
In.close();
}
cout << "System Dictionary consists " << counter
<< " words,\nwith first letter ‘a‘ or ‘A‘"
<< endl;
cout << m1.count(‘A‘) << " words start with ‘A‘"
<< endl;
Copyright: anatoliyurb Edited by snowman
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cout << m1.count(‘a‘) << " words start with ‘a‘"
<< endl;
M2::iterator low = m2. lower_bound("Aba");
M2::iterator upp = m2.upper_bound("Abe");
cout << "Range of the words from ‘Aba‘ to ‘Abe‘:"
<< endl;
while ( low != upp )
{
cout << (*low).first << endl;
low++;
}
return 0;
}
OUTPUT:
// System Dictionary consists 3577 words,
// with first letter ‘a‘ or ‘A‘
// 491 words start with ‘A‘
// 3086 words start with ‘a‘
// Range of the words from ‘Aba‘ to ‘Abe‘:
// Ababa
// Abba
// Abbott
// Abby
// Abe
key_comp
returns the function that compares keys
#include <iostream>
#include <map>
OUTPUT:
max_size
the maximum number of elements that the maltimap can hold
#include <iostream>
#include <map>
using namespace std;
Copyright: anatoliyurb Edited by snowman
- 128 -
int main ()
{
typedef multimap<int, char, greater<int> > M;
typedef M::value_type v_t;
M m;
m.insert(v_t(2,‘B‘));
m.insert(v_t(3,‘C‘));
m.insert(v_t(1,‘A‘));
M::iterator It = m.begin();
cout << "m:" << endl;
while ( It != m.end() )
{
cout << (*It).first << " - "
<< (*It).second
<< endl;
It++;
}
cout << "size of multimap ‘m‘ "
<< m.size() << endl;
cout << "max_size of ‘m‘ "
<< m. max_size() << endl;
return 0;
}
OUTPUT:
// m:
// 3 - C
// 2 - B
// 1 - A
// size of multimap ‘m‘ 3
// max_size of ‘m‘ 4294967295
rbegin
returns a reverse iterator to the end of the maltimap
#include <iostream>
#include <map>
#include <iomanip>
#include <string>
using namespace std;
Copyright: anatoliyurb Edited by snowman
- 129 -
template<class T>
class ID
{
public:
ID(T t, T n) : id(t), name(n) {}
void print ()
{
cout.setf(ios::left);
cout << setw(15) << name.c_str()
<< id << endl;
cout.unsetf(ios::left);
}
private:
T id, name;
};
//======================================
int main ()
{
typedef ID<string> Id;
typedef multimap<int, Id> M;
typedef M::value_type v_t;
M m;
m.insert(v_t(1,Id("000123","Shevchenko")));
m.insert(v_t(2,Id("000124","Pushkin")));
m.insert(v_t(3,Id("000125","Shakespeare")));
// same key
m.insert(v_t(3,Id("000126","Smith")));
M::reverse_iterator It = m. rbegin();
while ( It != m.rend() )
{
cout.setf(ios::left);
cout << setw(3) << (*It).first;
It->second.print();
It++;
}
return 0;
}
OUTPUT:
// 3 Smith 000126
// 3 Shakespeare 000125
Copyright: anatoliyurb Edited by snowman
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// 2 Pushkin 000124
// 1 Shevchenko 000123
rend
returns a reverse iterator to the beginning of the maltimap
#include <iostream>
#include <map>
#include <iomanip>
#include <string>
using namespace std;
template<class T>
class ID
{
public:
ID(T t, T n) : id(t), name(n) {}
void print ()
{
cout.setf(ios::left);
cout << setw(15) << name.c_str()
<< id << endl;
cout.unsetf(ios::left);
}
private:
T id, name;
};
//======================================
int main ()
{
typedef ID<string> Id;
typedef multimap<int, Id> M;
typedef M::value_type v_t;
M m;
m.insert(v_t(1,Id("000123","Shevchenko")));
m.insert(v_t(2,Id("000124","Pushkin")));
m.insert(v_t(3,Id("000125","Shakespeare")));
// same key
m.insert(v_t(3,Id("000126","Smith")));
M::reverse_iterator It = m.rbegin();
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while ( It != m. rend() )
{
cout.setf(ios::left);
cout << setw(3) << (*It).first;
It->second.print();
It++;
}
return 0;
}
OUTPUT:
// 3 Smith 000126
// 3 Shakespeare 000125
// 2 Pushkin 000124
// 1 Shevchenko 000123
size
the number of elements in the maltimap
#include <iostream>
#include <map>
#include <iomanip>
#include <string>
using namespace std;
template<class T>
class ID
{
public:
ID(T t, T n) : id(t), name(n) {}
void print ()
{
cout.setf(ios::left);
cout << setw(15) << name.c_str()
<< id << endl;
cout.unsetf(ios::left);
}
private:
T id, name;
};
//======================================
int main ()
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{
typedef ID<string> Id;
typedef multimap<int, Id> M;
typedef M::value_type v_t;
M m;
m.insert(v_t(1,Id("000123","Shevchenko")));
m.insert(v_t(2,Id("000124","Pushkin")));
m.insert(v_t(3,Id("000125","Shakespeare")));
// same key
m.insert(v_t(3,Id("000126","Smith")));
cout << "size of multimap ‘m‘ = "
<< m.size() << endl;
M::iterator It = m.begin();
while ( It != m.end() )
{
cout.setf(ios::left);
cout << setw(3) << (*It).first;
It->second.print();
It++;
}
return 0;
}
OUTPUT:
// size of multimap ‘m‘ = 4
// 1 Shevchenko 000123
// 2 Pushkin 000124
// 3 Shakespeare 000125
// 3 Smith 000126
swap
exchanges two maltimaps
#include <iostream>
#include <map>
#include <list>
#include <numeric>
#include <algorithm>
using namespace std;
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typedef multimap<int, list<int> > M;
void print (M m)
{
M::iterator It = m.begin();
list<int>::iterator Li;
while ( It != m.end() )
{
cout << "key : " << (*It).first
<< "; value : ";
for ( Li = It->second.begin();
Li != It->second.end(); Li++ )
cout << *Li << " ";
It++;
}
cout << endl;
}
//-------------------------------------------
int main ()
{
list<int> L1, L2;
L1.push_back(1);
L1.push_back(2);
L1.push_back(3);
copy(L1.begin(),L1.end(),
back_inserter(L2));
M m1, m2;
m1.insert(M::value_type(1,L1));
m2.insert(M::value_type(2,L2));
cout << "multimap m1:" << endl;
print(m1);
cout << "multimap m2:" << endl;
print(m2);
if ( m1 == m2 )
cout << "multimaps m1 and m2 are equal"
<< endl;
else
{
cout << endl << "After m1.swap(m2)"
<< endl;
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m1. swap(m2);
cout << "multimap m1:" << endl;
print(m1);
cout << "multimap m2:" << endl;
print(m2);
}
return 0;
}
OUTPUT:
// multimap m1:
// key : 1; value : 1 2 3
// multimap m2:
// key : 2; value : 1 2 3
//
// After m1.swap(m2)
// multimap m1:
// key : 2; value : 1 2 3
// multimap m2:
// key : 1; value : 1 2 3
upper_bound
returns an iterator to the first element greater than
a certain value
#include <iostream>
#include <map>
#include <string>
#include <fstream>
using namespace std;
int main ()
{
typedef multimap<char,string> M1;
typedef M1::value_type v_t1;
M1 m1;
typedef multimap<string,char,less<string> > M2;
typedef M2::value_type v_t2;
M2 m2;
string word;
int counter = 0;
Copyright: anatoliyurb Edited by snowman
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ifstream In("/usr/share/dict/words");
if ( In.good() )
{
while(1)
{
getline(In,word);
char ch = word.at(0);
// file is sorted
if ( ch != ‘A‘ && ch != ‘a‘ )
break;
else
{
// for conting of words
m1.insert(v_t1(ch,word));
// for upper-lower bound
m2.insert(v_t2(word,ch));
}
counter++;
}
In.close();
}
cout << "System Dictionary consists " << counter
<< " words,\nwith first letter ‘a‘ or ‘A‘"
<< endl;
cout << m1.count(‘A‘) << " words start with ‘A‘"
<< endl;
cout << m1.count(‘a‘) << " words start with ‘a‘"
<< endl;
M2::iterator low = m2.lower_bound("Aba");
M2::iterator upp = m2. upper_bound("Abe");
cout << "Range of the words from ‘Aba‘ to ‘Abe‘:"
<< endl;
while ( low != upp )
{
cout << (*low).first << endl;
low++;
}
return 0;
}
OUTPUT:
// System Dictionary consists 3577 words,
Copyright: anatoliyurb Edited by snowman
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// with first letter ‘a‘ or ‘A‘
// 491 words start with ‘A‘
// 3086 words start with ‘a‘
// Range of the words from ‘Aba‘ to ‘Abe‘:
// Ababa
// Abba
// Abbott
// Abby
// Abe
value_comp
returns the function that compares values
#include <iostream>
#include <map>
OUTPUT:
// 容器适配器
stack
all stack functions
// The C++ Stack is a container adapter that gives the
// programmer the functionality of a stack -- specifically,
// a FILO (first-in, last-out) data structure.
// push, pop, size, top, empty
#include <iostream>
#include <stack>
#include <vector>
#include <algorithm>
#include <numeric>
using namespace std;
int main ()
{
vector<int> v1(5), v2(5), v3(5);
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iota(v1.begin(), v1.end(), 0);
iota(v2.begin(), v2.end(), 5);
iota(v3.begin(), v3.end(), 10);
stack<vector<int> > s s;
s. push(v1);
s. push(v2);
s. push(v3);
cout << "size of stack ‘s‘ = "
<< s. size() << endl;
if ( v3 != v2 )
s. pop();
cout << "size of stack ‘s‘ = "
<< s. size() << endl;
vector<int> top = s. top();
cout << "Contents of v2 : ";
copy(top.begin(),top.end(),
ostream_iterator(cout," "));
cout << endl;
while ( !s. empty() )
s. pop();
cout << "Stack ‘s‘ is " << (s. empty() ? ""
: "not ") << "empty" << endl;
return 0;
}
OUTPUT:
// size of stack ‘s‘ = 3
// size of stack ‘s‘ = 2
// Contents of v2 : 5 6 7 8 9
// Stack ‘s‘ is empty
Queue
Copyright: anatoliyurb Edited by snowman
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all queue functions
// Queue is a container adapter that gives
// the programmer a FIFO (first-in, first-out)
// data structure.
// push, pop, size, front, back, empty
#include <iostream>
#include <queue>
#include <string>
using namespace std;
int main ()
{
string s1("C++");
string s2("is");
string s3("powerfull");
string s4("language");
queue que;
que. push(s1);
que. push(s2);
que. push(s3);
que. push(s4);
cout << "size of queue ‘que‘ = "
<< que. size() << endl;
string temp = que. back();
cout << temp << endl;
while ( !que. emp ty() )
{
temp = que. front();
cout << temp << " ";
que. pop();
}
cout << endl;
return 0;
}
OUTPUT:
// size of queue ‘que‘ = 4
// language
// C++ is powerfull language
Copyright: anatoliyurb Edited by snowman
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priority_queue
all priority_queue functions
// Priority Queues are like queues, but the
// elements inside the data structure are
// ordered by some predicate.
#include <iostream>
#include <queue>
#include <vector>
#include <string>
using namespace std;
int main ()
{
priority_queue<int, vector<int>, less<int> > ipq;
ipq. push(100);
ipq. push(200);
ipq. push(300);
cout << "size of priority_queue ipq = "
<< ipq. size() << endl;
cout << "ipq <int,vector<int>, less<int> > = ";
while ( !ipq. empty() )
{
cout << ipq. top() << " ";
ipq. pop();
}
cout << endl << endl;
cout << "priority_queue<string,vector<string> > spq;"
<< endl;
priority_queue<string,vector<string> > spq;
for ( int i=1; i<10; i++ )
spq. push(string(i,‘*‘));
while ( !spq. empty() )
{
cout << spq. top() << endl;
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spq. pop();
}
return 0;
}
OUTPUT:
// size of priority_queue ipq = 3
// ipq <sring,vector<string> > = 300 200 100
//
// priority_queue<string,vector<string> > spq;
// *********
// ********
// *******
// ******
// *****
// ****
// ***
// **
// *