第五章 编程练习

第一题

 1 #include<iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     int a,b,sum=0;
 6     cin>>a>>b;
 7     for(int i=a;i<=b;i++)
 8         sum+=i;
 9     cout<<sum;
10     return 0;
11 }

第二题

 1 #include<iostream>
 2 #include<array>
 3 using namespace std;
 4 int main()
 5 {
 6     array<long double,100>arr;
 7     arr[0]=arr[1]=1l;
 8     for(int i=2;i<20;i++)
 9     {
10         arr[i]=i*arr[i-1];
11         cout<<i<<"!="<<arr[i]<<endl;
12     }
13     return 0;
14 }

第三题

 1 #include<iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     double sum=0,a;
 6     cout<<"enter the number";
 7     cin>>a;
 8     for(;a!=0;)
 9     {
10         sum+=a;
11         cin>>a;
12     }
13     cout<<sum;
14     return 0;
15 }

第四题

 1 #include<iostream>
 2 using namespace std;
 3 const float a=100.0;
 4 float daphne(int n)
 5 {
 6     float da;
 7     da=a+a*0.1*n;
 8     return da;
 9 }
10
11 float cleo(int n)
12 {
13     float cl=a*(1+0.05);
14     for(int i=1;i<n;i++)
15     {
16         cl=cl*(1+0.05);
17     }
18     return cl;
19 }
20
21 int main()
22 {
23     float b,c;
24     int i;
25     for(i=1;;i++)
26     {
27         b=daphne(i);
28         c=cleo(i);
29         if(c>b)break;
30     }
31     cout<<"year="<<i<<endl;
32     cout<<"dephne="<<b<<endl;
33     cout<<"cleo="<<c<<endl;
34     return 0;
35
36 }
37 网上下载版
38 #include <iostream>
39 using namespace std;
40 void main()
41 {
42     double Dsum=100;
43     double Csum=100;
44     int i=0;
45     while (Csum<=Dsum)
46     {
47         Dsum+=10;
48         Csum+=Csum*0.05;
49         i++;
50     }
51     cout<<"After "<<i<<" year, Csum is bigger than Dsum"<<endl;
52     cout<<"Dsum="<<Dsum<<"   Csum="<<Csum;
53     cin.get();
54 }

第五题

 1 #include<iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     char*mon[12]={"1","2","3","4","5","6","7","8","9","10","11","12"};
 6     int num[12];
 7     int sum=0;
 8     for(int i=0;i<12;i++)
 9     {
10         cout<<"enter the number of the No."<<mon[i]<<" monthe .";
11         cin>>num[i];
12         sum+=num[i];
13     }
14     cout<<sum;
15     return 0;
16 }

第六题

 1 #include<iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     char*mon[3][12]={"1","2","3","4","5","6","7","8","9","10","11","12","1","2","3","4","5","6","7","8","9","10","11","12","1","2","3","4","5","6","7","8","9","10","11","12"};
 6     int num[3][12];
 7     int sum[4]={0};
 8     for(int j=0;j<3;j++)
 9     {
10         for(int i=0;i<12;i++)
11         {
12             cout<<"enter the number of the No."<<mon[j][i]<<" monthe .";
13             cin>>num[j][i];
14             sum[j]+=num[j][i];
15         }
16     }
17     cout<<sum[0]<<","<<sum[1]<<","<<sum[2]<<","<<sum[0]+sum[1]+sum[2]<<","<<endl;;
18     return 0;
19 }

第七题

 1 #include<iostream>
 2 #include<string>
 3 using namespace std;
 4 struct car
 5 {
 6     string make;
 7     int year;
 8 };
 9 int main()
10 {
11     int n;
12     cout<<"how may do you wish to catalog? ";
13     cin>>n;
14     car*ps=new car[n];
15     for(int i=0;i<n;i++)
16     {
17         cin.get();
18         cout<<"Car #"<<i+1<<endl;
19         cout<<"please enter the make: ";
20         getline(cin,ps[i].make);
21         cout<<"please enter the year made: ";
22         cin>>ps[i].year;
23     }
24     cout<<"here is your collection"<<endl;
25     for(int i=0;i<n;i++)
26     {
27         cout<<ps[i].year<<" "<<ps[i].make<<endl;
28     }
29     return 0;
30 }

第八题

 1 #include<iostream>
 2 #include<cstring>
 3 using namespace std;
 4 int main()
 5 {
 6     char word[20];
 7     int i=0;
 8     cout<<"enter words(to stop, type the word done):"<<endl;
 9     cin>>word;
10     while(strcmp(word,"done")!=0)
11     {
12         i++;
13         cin>>word;
14     }
15     cout<<"you entered a total of "<<i<<" words."<<endl;
16     return 0;
17 }

首先输入整个字符串，cin读取第一个单词，就是空格之前的，空格之后的被保留。

继续cin输入时，在读取保留的部分的第一个单词。

第九题

 1 #include<iostream>
 2 #include<string>
 3 using namespace std;
 4 int main()
 5 {
 6     string word;
 7     cout<<"enter words(to stop, type the word done):"<<endl;
 8     cin>>word;
 9     int count=0;
10     for(;word!="done";)
11     {
12         count++;
13         cin>>word;
14     }
15     cout<<"you entered a total of "<<count<<" words."<<endl;
16     return 0;
17 }

第十题

 1 #include<iostream>
 2 using   namespace std;
 3 int main()
 4 {
 5     int i;
 6     cout<<"enter number of rows ";
 7     cin>>i;
 8     for(int j=0;j<i;j++)
 9     {
10         int k=4-j,m=j+1;
11         for(int n=0;n<k;n++)
12         {cout<<".";}
13         for(int n=0;n<m;n++)
14         {cout<<"*";}
15         cout<<endl;
16     }
17     return 0;
18 }