这是一个给小学生出加法题的问题

/* Note:Your choice is C IDE */
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void main()
{
 int a,b,c,d,e,i=1,j=1;
 for(;i<=3;i++)
{
 srand(time(NULL));
 a=(rand()%100+1)/10+1;
 b=(rand()%100+1)/10+1;
 loop:e=(rand()%100+1)/10+1;
 if(e<=4)
 {if(e==1)
    {c=a+b;
 printf("please account %d+%d=?\n",a,b);}
    else if(e==2)
    {c=a-b;printf("please account %d-%d=?\n",a,b);}
    else if(e==3)
    {c=a*b;printf("please account %d*%d=?\n",a,b);}
    else
    {c=a/b;printf("please account %d/%d=?\n",a,b);}
 }
 else
 goto loop;
 scanf("%d",&d);
 if(d==c)
 {printf("right\n");j++;}
 }  
printf("test over.\n");
printf("score=%d\n",(j-1)*10);
printf("the wrong number is %d",4-j);
}