排序之set集合排序

#include <iostream>
#include <string>
#include <set>
#include <sstream>
using namespace std;

set<int> dict;

int main()
{
    int num;
	cout<<"输入一串数字，以0结束"<<endl;
	while (cin>>num,num)
	{
		dict.insert(num);
	}
	cout<<"排序之后"<<endl;
	for (set<int>::iterator it = dict.begin();it != dict.end();it++)
	{
		cout<<*it<<" ";
	}
	cout<<endl;
	return 0;
}

升序排列

#include <iostream>  //对于重复的数字将会忽略
#include <string>
#include <set>
#include <sstream>
using namespace std;

set<int> dict;

int main()
{
    int num,flag=1;
	cout<<"输入一串数字，以0结束"<<endl;
	while (cin>>num,num)
	{
		dict.insert(num);
	}
	cout<<"排序之后"<<endl;
	for (set<int>::iterator it = dict.end();it != dict.begin();it--)
	{
		if(flag)  it--,flag=0;
		cout<<*it<<" ";
	}
	cout<<*(dict.begin());
	cout<<endl;
	return 0;
}

降序排列

也可以用反向迭代

#include <iostream>
#include <string>
#include <set>
#include <sstream>
using namespace std;

set<int> dict;

int main()
{
    int num;
	cout<<"输入一串数字，以0结束"<<endl;
	while (cin>>num,num)
	{
		dict.insert(num);
	}
	cout<<"排序之后"<<endl;
	for (set<int>::reverse_iterator it = dict.rbegin();it != dict.rend();it++)
	{
		cout<<*it<<" ";
	}
	cout<<endl<<dict.size()<<endl;//验证重复元素不会插入
	return 0;
}

或者自定义比较规则

1.元素不是结构体

#include <iostream>
#include <string>
#include <set>
#include <sstream>
using namespace std;

struct mycom
{
	bool operator () (const int &a,const int &b) //重载（）
	{
		if (a != b)
		{
			return a>b;
		}
		else
			return a>b;
	}
};

int main()
{
    int num;
	set<int,mycom> dict;
	cout<<"输入一串数字，以0结束"<<endl;
	while (cin>>num,num)
	{
		dict.insert(num);
	}
	cout<<"排序之后"<<endl;
	for (set<int,mycom>::iterator it = dict.begin();it != dict.end();it++)
	{
		cout<<*it<<" ";
	}

	cout<<endl<<dict.size()<<endl;//验证重复元素不会插入
	return 0;
}

2.元素是结构体

#include<iostream>
#include<set>
#include<string>
using namespace std;
struct Info
{
	string name;
	double score;
	bool operator < (const Info &a) const // 重载“<”操作符，自定义排序规则
	{
		//按score由大到小排序。如果要由小到大排序，使用“>”即可。
		return a.score < score;
	}
};
int main()
{
	set<Info> s;
	Info info;

	//插入三个元素
	info.name = "Jack";
	info.score = 80;
	s.insert(info);
	info.name = "Tom";
	info.score = 99;
	s.insert(info);
	info.name = "Steaven";
	info.score = 60;
	s.insert(info);

	set<Info>::iterator it;
	for(it = s.begin(); it != s.end(); it++)
		cout << (*it).name << " : " << (*it).score << endl;
	return 0;
}

删除与清空

#include <iostream>
#include <string>
#include <set>
#include <sstream>
using namespace std;

set<int> dict;

int main()
{
    int num;
	cout<<"输入一串数字，以0结束"<<endl;
	while (cin>>num,num)
	{
		dict.insert(num);
	}
	cout<<"(升序)排序之后"<<endl;
	for (set<int>::iterator it = dict.begin();it != dict.end();it++)
	{
		cout<<*it<<" ";
	}
    cout<<endl;

	cout<<"需要删除的数字为 ";
	cin>>num;
	dict.erase(num);
    for (set<int>::reverse_iterator rit = dict.rbegin();rit != dict.rend();rit++)
	{
		cout<<*rit<<" ";
	}

	cout<<endl<<"清空之后 ";
	dict.clear();
	cout<<endl<<dict.size()<<endl;//验证重复元素不会插入
	return 0;
}

查找

#include <iostream>
#include <string>
#include <set>
#include <sstream>
using namespace std;

set<int> dict;

int main()
{
    int num;
	cout<<"输入一串数字，以0结束"<<endl;
	while (cin>>num,num)
	{
		dict.insert(num);
	}
	cout<<"(升序)排序之后"<<endl;
	for (set<int>::iterator it = dict.begin();it != dict.end();it++)
	{
		cout<<*it<<" ";
	}
    cout<<endl;

    cout<<"查找的数为 ";
	cin>>num;
	it = dict.find(num);
    if(it == dict.end())
		cout<<"not found";
	else
		cout<<*it;
	cout<<endl<<dict.size()<<endl;//验证重复元素不会插入
	return 0;
}