小学生四则运算

#include<stdio.h>
#include <iostream>
#include <ctime>
using namespace std;
int main()
{
int a,b,c,d=0,x,z,i,y,o;
srand(time(NULL));
printf("\t\t\t**************************\n");
printf("\t\t\t欢迎进入小学四则运算测试系统\n");
printf(" \t\t\t1.进入测试 \n");
printf(" \t\t\t2.退出程序 \n");
printf("\t\t\t**************************\n");
printf("\t\t\t请用户输入：");
scanf("%d",&z);
if (z==1)
{
printf("\t\t\t测试开始！\n");
printf("\t\t\t答对1题得10分，答错不得分！\n");
for(i=1;i<11;i++)
{
a=rand()%100;
b=rand()%100;
x=rand()%4;
o=rand()%10;
switch(x)
{
case 0:
{
y=a+b;
printf("请看题:");
printf("%d+%d=",a,b);
scanf("%d",&c);
if (y==c)
{
d+=10;
printf("答对了,现在得分%d\n",d);
}
else printf("答错了，不得分！\n");
break;
}
case 1:
{
if (b>a)
{
z=a;
a=b;
b=z;
}
y=a-b;
printf("请看题:");
printf("%d-%d=",a,b);
scanf("%d",&c);
if (y==c)
{
d+=10;
printf("答对了,现在得分%d\n",d);
}
else printf("答错了，不得分！\n");
break;
case 2:
{
if (a>10)
{
a=a/10;
}
if (b>10)
{
b=b/10;
}
y=a*b;
printf("请看题:");
printf("%d*%d=",a,b);
scanf("%d",&c);
if (y==c)
{
d+=10;
printf("答对了,现在得分%d\n",d);
}
else printf("答错了，不得分！\n");
break;
}
case 3:
{
if (b>10)
{
b=b/10;
}
if (!(a%b==0))
{
a=b*o;
}
y=a/b;
printf("请看题:");
printf("%d/%d=",a,b);
scanf("%d",&c);
if (y==c)
{
d+=10;
printf("答对了,现在得分%d\n",d);
}
else printf("答错了，不得分！\n");
break;
}
}
}
}
}
else
{
cout<<"谢谢使用\n";
return 0;
}
switch(d/10)
{
case 10: printf("真是个天才！\n");break;
case 9: printf("真聪明！\n");break;
case 8: printf("还不错！\n");break;
case 7: printf("多多加油！\n");break;
case 6: printf("刚及格，还得多练习！\n");break;
case 5:
case 4:
case 3:
case 2:
case 1:
case 0: printf("不及格！\n");break;
}

return 0;
}