简单的四则运算

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
void main()
{
int a,b,c,d;
int total1=0,total2=0;
while(1)
{
srand(time(NULL));
d=a=rand()%100;
b=(rand()%a+a)%100;
if(a%4==1&&a<b)c=a,a=b,b=c;
if(b==0&&a%4==3)b=rand()%10+1;
if(a%4==3&&a%b!=0)
{
srand(time(0));
a=b*(rand()%a);
}
switch(d%4)
{
case 0:printf("%d ＋ %d = ",a,b);break;
case 1:printf("%d － %d = ",a,b);break;
case 2:printf("%d × %d = ",a,b);break;
case 3:printf("%d ÷ %d = ",a,b);break;
}
scanf("%d",&c);
switch(d%4)
{
case 0:if(c==a+b){printf("正确\n");total1++;}else {printf("错误\n");total2++;}break;
case 1:if(c==a-b){printf("正确\n");total1++;}else {printf("错误\n");total2++;}break;
case 2:if(c==a*b){printf("正确\n");total1++;}else {printf("错误\n");total2++;}break;
case 3:if(c==a/b){printf("正确\n");total1++;}else {printf("错误\n");total2++;}break;
}
printf("按任意键继续，Q退出！\n");
fflush(stdin);
if(getchar()=='Q')break;
}
printf("你答对了%d道题，答错%d道题\n",total1,total2);
}