while(open){
      printf("choice:>");
      scanf("%d",&choice);
      switch(choice){
      case 4:break;
      case 5:break;
      case 6:break;
      case 7:break;
      case 8:break;
      case 9:break;
      case 10:break;
      case 11:break;
      case 12:{
          open=0;
          break;
              }
      }
  }

choice是int型，如果在输入过程中输入比如字母之类的会出玩死循环。。。