#include <stdio.h>
main()
{

      int a = 0, b = 0 , c = 0 ;
      
      printf("请输入a的值: ");
   
      scanf("%d",&a);
   
      printf("请输入b的值: ");
   
      scanf("%d",&b);
   
            {
             if  (a >= 50 , b >= 50)
     
                 c = a * b;
        
                   else if (a >= 50 , b <= 50)
        
                   c = a - b;
               
             else  (a <= 50 , b <= 50)
     
                   c = a + b;
            
   printf("计算结果为: ");
   
   printf("%d\n",c);
            }

      while(1)
      {   
      char c;
      
      printf("请选择继续y或者离开n\n");

      fflush(stdin);
     
      c=getchar();

      if(c=='y')

      continue;
      
      else
      
      break;
      }
      
      return main;
   
}   

可以考虑将运算判断的那段函数放在子函数中,C语言是由函数组成的，可以模块化
在主函数中只有

int main()
{
    int flag = 1;    //当flag为真
    char ch_select;
    do
    {   
        system("cls");
        judgement(a , b, c,);
        
        printf("请问您是否要继续（Y|N）");
        scanf("%c",&ch_select);
        getchar();
        if(ch_select=='Y'||ch_select=='y')
        {
            flag = 1; 
        }
        else
        {
            flag = 0;    
        }  
    }while(flag==1);

    return 0;
}

[此贴子已经被作者于2016-9-18 23:27编辑过]

上面程序开始就无法运行，这个原程序可以用其他函数执行，那么应该如何用数组   指针运行

这个程序在输入完毕显示后，如何返回到开头继续执行，当然要出现询问是否继续执行，不然会死循环
#include <stdio.h>
main()
{

      int a = 0, b = 0 , c = 0 ;
      
      printf("请输入a的值: ");
   
      scanf("%d",&a);
   
      printf("请输入b的值: ");
   
      scanf("%d",&b);
   
            {
             if  (a >= 50 , b >= 50)
     
                 c = a * b;
        
                    if (a>=50 , b <= 50 )
        
                       c = a - b;
               
                       if (a <= 50 , b <= 50)
                       
                           c = a / b;
                           
                           if(a <= 50 , b >=50)
                           
                             c = a + b;
                    
            
   printf("计算结果为: ");
   
   printf("%d\n",c);
            }
}

你if语句好像用错了吧 应该写成这样的吧
if(a>=50&&b>=50)
{
执行的语句；
}

不会死循环吧

#include <stdio.h>
main()
{
      int a = 0, b = 0 , c = 0 ;
    while(1)
    {
      char i;
      printf("请选择继续y或者离开n\n");
      i=getchar();
        if(i=='Y'){
      printf("请输入a的值: ");
      scanf("%d",&a);
      printf("请输入b的值: ");
      scanf("%d",&b);
      if  (a >= 50&&b >= 50)
        { c = a * b;}
        else if (a >= 50&&b<= 50)
          {c = a - b;}         
          else  (a <= 50&&b <= 50)
             {c = a + b;}
       printf("计算结果为:%d\n ",c);
               continue;
       }
    else {break;}
     return ;
}

[此贴子已经被作者于2016-9-18 22:11编辑过]