C语言 猜数字游戏

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void guess()
{
int input = 0;
int ret;
srand((unsigned int)time(NULL));
ret = rand() % 100;
printf("请输入0-100内的数字\n");
do
{
scanf("%d",&input);
if(input < ret)
printf("猜小了!!!");
else if(input > ret)
printf("猜大了!!!");
}while(ret != input);
printf("猜对了");
}
void show()
{
int choice;
printf("************************\n");
printf("***欢迎使用猜数字游戏***\n");
printf("开始游戏：请按1\n");
printf("退出游戏：请按0\n");
printf("************************\n");
scanf("%d",&choice);
switch(choice)
{
case 1:guess();break;
default:return;
}

}
int main()
{
show();
system("pause");
return 0;
}