#include<stdio.h>
main()
{int i;
 void set_time_shutdown();
printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
n:
printf(" 请选择关机时间或自己设定关机时间 \n");
printf("~~~~~~~~~~~请选择~~~~~~~~~~~~~~~~~\n");
printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
printf("1、0:00:00关机！\n");
printf("2、1:00:00关机！\n");
printf("3、2:00:00关机！\n");
printf("4、3:00:00关机！\n");
printf("5、4:00:00关机！\n");
printf("6、5:00:00关机！\n");
printf("7、6:00:00关机！\n");
printf("8、7:00:00关机！\n");
printf("9、自己设定关机时间！\n");
printf("0、取消定时关机！\n");
printf("~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
printf("请选择：");
scanf("%d",&i);
switch(i)
{
case 1: system("at 18:54 shutdown -s");break;
case 2: system("at 1:00 shutdown -s");break;
case 3: system("at 2:00 shutdown -s");break;
case 4: system("at 3:00 shutdown -s");break;
case 5: system("at 4:00 shutdown -s");break;
case 6: system("at 5:00 shutdown -s");break;
case 7: system("at 6:00 shutdown -s");break;
case 8: system("at 7:00 shutdown -s");break;
case 9: set_time_shutdown();break;
case 0: system("shutdown -a");break;
default:printf("输入错误！请重新输入！");goto n;
}
}

void set_time_shutdown()
{
char a[2];
char b[2];
char buff[2];
char bull[2];
printf("请输入关机的小时数!（格式为1、2、3、4......）\n");
printf("请输入：");
scanf("%c",&a);
fprintf(buff,"%c:",a);
printf("\n");
printf("请输入关机的分钟数!（格式为01、02、03、04......）\n");
printf("请输入：");
scanf("%c",&b);
fprintf(bull,"%c:",b);
system("at buff:bull shutdown -s");
}

求教，为什么选择9的时候，输入小时那有错误！求高手指教！

scanf("%c",&a);
scanf("%c",&b);

应该要怎么改呢？ 我也知道是这里！

scanf("%s", a);
scanf("%s", b);