C语言：编写猜数字游戏，猜一个数字，一直到猜中为止

#include<stdio.h>
#include<stdlib.h>
#include<time.h>

int game()
{
int num = 0;
int ret = 0;
srand((unsigned int)time(NULL));
ret = rand();
ret = ret % 100;

while (1)
{
scanf("%d", &num);
if (num>ret)
{
printf("大了，请再猜！\n");
}
else if (num<ret)
{
printf("小了，请再猜！\n");
}
else
{
printf("恭喜您，猜中了！\n");
break;

}
}
return 0;
}

void menu()
{
printf("***************************\n");
printf("*** 欢迎体验猜字谜游戏! ***\n");
printf("******   1:开始游戏  ******\n");
printf("******   2:退出游戏  ******\n");
printf("***************************\n");
}

int main()
{
int ch = 0;
menu();
scanf("%d", &ch);

switch (ch)
{
case 1:
{
printf("我们开始吧!\n");
game();
break;
}
default:
{
printf("我们再见吧!\n");
return 0;
}
}
}