p132 4.7 哥德巴赫的验证.cpp

谭浩强 《C++ 程序设计》第三版的部分课后练习题源码

#include<iostream>
#include<cmath>
using namespace std;
int prime(int number)
{  int i,flag=3;
   for(i=2;i<=sqrt(number);i++)
   { if(number%i==0) {flag=0;
                      break;
   
                     }
    }
    
    return flag;
    
 }
 
 void gotbaha(int number)
 {   int i,a;
           for(i=2;i<number;i++)
           {  if(prime(i))  { a=number-i;
                               if(prime(a))    { cout<<number<<"="<<i<<"+"<<a;
                                                break; 
                                                }
                             }
                                
                                
            }
         
         
         
         
         
         }
      
      
      
      
      
   int main()
   { int number;
     do
   {  cout<<"please input the number:  ";
             cin>>number;  }
    while(!(number>6 && number%2==0));
    
    gotbaha(number);
     system("pause");  
    // else {goto step;}
     return 0;
       
       
       
       
       
       
       }