程序代码：

#include "stdafx.h"
#include <iostream.h>
int printstar(int num1,int num2)
{
int mid,a,b;
int yue=1;
   if (num1<num2)
   {mid=num2;
    num2=num1;
    num1=mid;
   }
    a=num1;
    b=num2;
   while(yue!=0)
   {
       if (a%b==0)
       {
           yue=b;
           break;
       }
       else 
       {
           yue=a%b;
           a=b;
           b=yue;
       }
   }
   cout<<"公约数是：";
   cout<<yue<<endl;
   if(yue!=1)
       return 1;
   else
       return 0;
   }
void main()
{
    int num,num0;
    cout<<"分母："<<endl;
    cin>>num;
    cout<<"分子："<<endl;
    cin>>num0;
    if(printstar(num,num0)==1)
        cout<<"不是最简"<<endl;
    else
        cout<<"是最简"<<endl;
}