二年级四则运算题

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
void main()
{
int a, b, c, d, e, i, j;
srand(time(NULL));
printf("二年级四则运算题\n");
for (i = 0; i < 30; i++)
{
a = rand() % 100;
b = rand() % 100;
c = rand() % 4;
switch (c)
{
case 0:
printf("%d+%d=\n", a, b);
break;
case 1:
if (a < b)
{
printf("%d-%d=\n", b, a);
}
else
printf("%d-%d=\n", a, b);
break;
case 2:
printf("%d*%d=\n", a, b);
break;
case 3:
{
d = rand() % 20;
if (d != 0)
e = rand() % 4;
switch (e)
{
case 0:
printf("%d÷%d=\n", d, d);
break;
case 1:
j = 2 * d;
printf("%d÷%d=\n", j, d);
break;
case 2:
j = 3 * d;
printf("%d÷%d=\n", j, d);
break;
case 3:
printf("0÷%d=\n", d);
break;
}
break;
}
}
}
system("pause");
}