第五章 编程练习

第一题

#include<iostream>
using namespace std;
int main()
{
    int a,b,sum=0;
    cin>>a>>b;
    for(int i=a;i<=b;i++)
        sum+=i;
    cout<<sum;
    return 0;
}

第二题

#include<iostream>
#include<array>
using namespace std;
int main()
{
    array<long double,100>arr;
    arr[0]=arr[1]=1l;
    for(int i=2;i<20;i++)
    {
        arr[i]=i*arr[i-1];
        cout<<i<<"!="<<arr[i]<<endl;
    }
    return 0;
}

第三题

#include<iostream>
using namespace std;
int main()
{
    double sum=0,a;
    cout<<"enter the number";
    cin>>a;
    for(;a!=0;)
    {
        sum+=a;
        cin>>a;
    }
    cout<<sum;
    return 0;
}

第四题

#include<iostream>
using namespace std;
const float a=100.0;
float daphne(int n)
{
    float da;
    da=a+a*0.1*n;
    return da;
}

float cleo(int n)
{
    float cl=a*(1+0.05);
    for(int i=1;i<n;i++)
    {
        cl=cl*(1+0.05);
    }
    return cl;
}

int main()
{
    float b,c;
    int i;
    for(i=1;;i++)
    {
        b=daphne(i);
        c=cleo(i);
        if(c>b)break;
    }
    cout<<"year="<<i<<endl;
    cout<<"dephne="<<b<<endl;
    cout<<"cleo="<<c<<endl;
    return 0;

}

网上下载版
#include <iostream>  
using namespace std;  
void main()  
{  
    double Dsum=100;  
    double Csum=100;  
    int i=0;  
    while (Csum<=Dsum)  
    {  
        Dsum+=10;  
        Csum+=Csum*0.05;  
        i++;      
    }  
    cout<<"After "<<i<<" year, Csum is bigger than Dsum"<<endl;  
    cout<<"Dsum="<<Dsum<<"   Csum="<<Csum;  
    cin.get();  
}

第五题

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

第六题

#include<iostream>
using namespace std;
int main()
{
    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"};
    int num[3][12];
    int sum[4]={0};
    for(int j=0;j<3;j++)
    {
        for(int i=0;i<12;i++)
        {
            cout<<"enter the number of the No."<<mon[j][i]<<" monthe .";
            cin>>num[j][i];
            sum[j]+=num[j][i];
        }
    }
    cout<<sum[0]<<","<<sum[1]<<","<<sum[2]<<","<<sum[0]+sum[1]+sum[2]<<","<<endl;;
    return 0;
}

第七题

#include<iostream>
#include<string>
using namespace std;
struct car
{
    string make;
    int year;
};
int main()
{
    int n;
    cout<<"how may do you wish to catalog? ";
    cin>>n;
    car*ps=new car[n];
    for(int i=0;i<n;i++)
    {
        cin.get();
        cout<<"Car #"<<i+1<<endl;
        cout<<"please enter the make: ";
        getline(cin,ps[i].make);
        cout<<"please enter the year made: ";
        cin>>ps[i].year;
    }
    cout<<"here is your collection"<<endl;
    for(int i=0;i<n;i++)
    {
        cout<<ps[i].year<<" "<<ps[i].make<<endl;
    }
    return 0;
}

第八题

#include<iostream>
#include<cstring>
using namespace std;
int main()
{
    char word[20];
    int i=0;
    cout<<"enter words(to stop, type the word done):"<<endl;
    cin>>word;
    while(strcmp(word,"done")!=0)
    {
        i++;
        cin>>word;
    }
    cout<<"you entered a total of "<<i<<" words."<<endl;
    return 0;
}

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

#include<iostream>
#include<string>
using namespace std;
int main()
{
    string word;
    cout<<"enter words(to stop, type the word done):"<<endl;
    cin>>word;
    int count=0;
    for(;word!="done";)
    {
        count++;
        cin>>word;
    }
    cout<<"you entered a total of "<<count<<" words."<<endl;
    return 0;
}

第十题

#include<iostream>
using   namespace std;
int main()
{
    int i;
    cout<<"enter number of rows ";
    cin>>i;
    for(int j=0;j<i;j++)
    {
        int k=4-j,m=j+1;
        for(int n=0;n<k;n++)
        {cout<<".";}
        for(int n=0;n<m;n++)
        {cout<<"*";}
        cout<<endl;
    }
    return 0;
}