#include<stdio.h>
 int main()
{  int account=0,x;
      
     
   for(;;){
      printf("1--清空，2--存钱");
      printf("3--取钱,4--查询余额\n");
      printf("请选择：");
      scanf("%d",&x);
         switch(x){
           case 1:
              account=0;
              break;
           case 2:
              printf("请输入要存入的金额：");
              int m;
              scanf("%d",&m);
              account=account+m;
              break;
           case 3:
              printf("请输入你要取出的金额：");
              int n;
              scanf("%d",&n);
              account=account-n;
              break;
           case 4:
              printf("你的余额是：%d\n",account);
              break;
         }
         if(x<1||x>4){
            printf("你输入的数字不正确！\n");
            scanf("%*c[^\n]");//清空缓冲区的固定格式
            scanf("%*c");//把\n也忽略掉
            continue;
         }   
   }
 }