实验一

书P63

2-28

（1）

#include<iostream>
using namespace std;
int main(){
    char select;
    while(1)
    {cout<<"Menu:A(dd) D(elete) S(ort) Q(uit),Select one:";
     cin>>select;
     if(select=='A')
         {cout<<"Data has added"<<endl;
          continue;}
     else if(select=='D')
         {cout<<"Data has deleted"<<endl;
          continue;}
     else if(select=='S')
         {cout<<"Data has sorted"<<endl;
          continue;}
     else if(select=='Q')
          break;
     else 
         cout<<"no such choice,please select again"<<endl;
    }
return 0;
}

 

（2）

#include<iostream>
using namespace std;
int main()
{char select;
 int i=1;
    while(i)
    {cout<<"Menu:A(dd) D(elete) S(ort) Q(uit),Select one:";
     cin>>select;
     if(select=='A'||select=='D'||select=='S'||select=='Q')
         {switch(select)
           {case 'A':cout<<"Data has added"<<endl;
                     break;
            case 'D':cout<<"Data has deleted"<<endl;
                     break;
            case 'S':cout<<"Data has sorted"<<endl;
                     break;
            case 'Q':i=0;
                     break;
           }
        }
     else 
         cout<<"no such choice,please select again"<<endl;
    }
return 0;
}

2-29

(1)while

#include<iostream> 
using namespace std;
int main()
{int n=2,i,flag;
 while(n<100)
  {i=2;flag=1;
   while(i<n)
    {if(n%i==0)
      {flag=0;
       break;
      } 
      i++; 
    }
    if(flag==1)
      cout<<n<<endl;
   n++;
  }
  return 0;
}

(2)do while

#include<iostream> 
using namespace std;
int main()
{int n=2,i,flag;
 do{
  i=2;flag=1;
  do{
      if(n%i==0)
      {flag=0;
       break;
      } 
      i++; 
  }while(i<n);
  if(flag==1)
      cout<<n<<endl;
   n++;
 } 
 while(n<100);
  return 0;
}

(3)for

#include<iostream>
#include<cmath>
using namespace std;
int main()
{int i,n,flag;
 for(i=2;i<=100;i++)
   {flag=1;
    for(n=2;n<=sqrt(i);n++)
       if(i%n==0)
       {flag=0;
         break;} 
    if(flag==1)
      cout<<i<<endl;
   } 
 return 0;
}

2-32

(1)do while

#include <cstdlib>
#include <iostream>
#include <ctime>
using namespace std;
int main()
{srand(time(0));
 int n,number;
 number=rand()%100+1;
 do 
 {cout<<"guess a number(1-100):";
  cin>>n;
  if(n>100)
    {cout<<"error";
     continue;
    }
if(n<number)
       cout<<"The number is bigger than yours"<<endl; 
  else if(n>number)
       cout<<"The nmuber is smaller than yours"<<endl;
 }while(n!=number);
 cout<<"congratulations!";
 return 0;
}

(2)while

#include <cstdlib>
#include <iostream>
#include <ctime>
using namespace std;
int main()
{srand(time(0));
 int n,number;
 number=rand()%100+1;
 while(1)
 {cout<<"guess a number(1-100):";
  cin>>n;
  if(n>100)
    {cout<<"error";
     continue;
    }
  if(n==number)
    {cout<<"congratulations!";
     break;
    }
  else if(n<number)
       cout<<"The number is bigger than yours"<<endl; 
  else if(n>number)
       cout<<"The nmuber is smaller than yours"<<endl;
 }
 return 0;
} 

2-34

#include<iostream>
using namespace std;
void f(int x)
{switch(x)
 {case 1:cout<<" red";
         break;
  case 2:cout<<" yellow";
         break;
  case 3:cout<<" blue";
         break;
  case 4:cout<<" white";
         break;
  case 5:cout<<" black";
         break; 
 }
}
int main()
{int i,j,k,n=1;
 for(i=1;i<=5;i++)
    for(j=1;j<=5;j++)
       for(k=1;k<=5;k++)
         if(i!=j&&i!=k&&j!=k)
          {cout<<n;
           f(i);
           f(j);
           f(k);
           cout<<endl;
           n++; 
          }  
return 0;
} 

实验总结:

①运行2-28时，输入某些标点，程序会出错。

②这四个程序和c语言程序差不多。输入输出语句不同。一些函数的头文件不一样，rand和srand函数不会用，通过老师给的网址查询一下就行了。

 

 

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