c语言第二次函数调用为啥不管用了呢？

#include<stdio.h>

int error = 0;

void judge(char flag, double *x, double *y, double *result)
{
   if(flag=='+')
           *result = *x+ *y;
   else if(flag=='-')
           *result = 1;
   else if(flag=='*')
           *result = (*x) * (*y);
   else if(flag=='/')
       {
           if(*y==0)
           {
               printf("输入格式有误\n");
               error = 1;
           }
           else
               *result = *x / *y;
       }
}

int main()
{
   double x=0.0, y=0.0, result=0, result1=0;
   int n = 1, sun=0;
   char flag;

   while(1)
   {
       int ling = 0;
       error = 0;
       printf("请输入算式\n");
       scanf("%lf %c %lf", &x, &flag, &y);
       judge(flag, &x, &y, &result);

       if(error==1)
       {
           ling=0;

       }
       else
       {
           printf("%.3lf", result);
           ling=1;
       }
       result1 = result;

       double z = 0.0;
       double result2 = 0;
       char flag1;



       while(ling)
       {

           scanf("%c", &flag1);
           if(flag1=='=')
           {
               printf("运算结果为%.3lf\n", result1);

               break;
           }
           else
           {
               scanf("%lf", &z);
               judge(flag1, &result1, &z, &result2);


               if(error==1)
               {
                   ling = 0;
                   break;
               }
               else
               {
                   printf("%.3lf", result2);
                   result1 = result2;

               }
           }
       }
   }
   return 0;
}