#include <stdio.h>  
#include <math.h>
#include <dos.h>
#include <conio.h>      
void main()
{
    struct time curtime;
    float th_hour,th_min,th_sec;    
    do
    {
        printf("*********************************************\n");
        printf("** This is a simple clock program.         **\n");
        printf("**                                         **\n");
        printf("*********************************************\n");
        printf("The current time is:\n");
        gettime(&curtime);   /*得到当前系统时间*/
        if((float)curtime.ti_hour<=12)         /*午前的处理*/
        {
            printf("AM ");
            if((float)curtime.ti_hour<10) printf("0");   /*十点之前在小时数前加零*/
            printf("%.0f:",(float)curtime.ti_hour);
        }
        else         /*午后的处理*/
        {
            printf("PM ");
            if((float)curtime.ti_hour-12<10) printf("0");
            printf("%.0f:",(float)curtime.ti_hour-12);
        }
        if((float)curtime.ti_min<10) printf("0");
        printf("%.0f:",(float)curtime.ti_min);
        if((float)curtime.ti_sec<10) printf("0");
        printf("%.0f",(float)curtime.ti_sec);
        printf("\n");
        printf("\n");
        printf("\n");
        printf("\n");
        printf("\n");
        printf("\n");
        sleep(1);      /*延时一秒后刷新*/
        clrscr();
    }while(1);
}