简单程序实现100以内加减乘除

include <stdio.h>

int main(void)
{
int i = 0, a, b, ret, user_ret;
char symbol;  0(+), 1(-), 2(*), 3(/)
int count, right = 0;

srand(time(NULL));

while (1) {
a = rand() % 100; 
b = rand() % 100;
symbol = rand() % 4;

switch (symbol) {
case 0 : {
ret = a + b;
symbol = ‘+‘; 
} break;

case 1 : {
ret = a - b;
symbol = ‘-‘;
} break;

case 2 : { 
ret = a * b;
symbol = ‘*‘;
} break;

case 3 : { 
ret = a / b;
symbol = ‘/‘;
}
}

printf("%d%c%d=", a, symbol, b);

count = 0;
while (1) {
scanf("%d", &user_ret);

if (user_ret == ret) { 
printf("回答正确\n");
right ++; 
break; 
}

printf("错误,再次输入:");
count++; // 答错计数+1

if (count == 3) { 
printf("正确答案是:%d\n", ret);
break; 
}
}

i++;

printf("是否继续(y/n)?\n");
getchar(); 
scanf("%c", &symbol);

if (symbol != ‘y‘ && symbol != ‘Y‘) 
break;
}

printf("练习结束, 共做题%d, 正确%d, 正确率%.2f%%\n", i, right, (double)right / i * 100);

return 0;
}