[em13]
#include<math.h>
#include<dos.h>
#include<graphics.h>
#define CENTERX 320   /*表盘中心位置*/
#define CENTERY 175
#define CLICK 100  /*喀嗒声频率*/
#define CLICKDELAY 30 /*喀嗒声延时*/
#define HEBEEP 10000 /*高声频率*/
#define LOWBEEP 500 /*低声频率*/
#define BEEPDELAY 200 /*报时声延时*/

/*表盘刻度形状*/
int Mrk_1[8]={-5,-160,5,-160,5,-130,-5,-130, };
int Mrk_2[8]={-5,-160,5,-160,2,-130,-2-130, };

/*时针形状*/
int HourHand[8]={-3,-100,3,-120,4, 10,-4,10};

/*分针形状*/
int MiHand[8]={-3,-120,3,-120,4, 10,-4,10};

/*秒针形状*/
int SecHand[8]={-2,-150,2,-150,3, 10,-3,10};

/*发出喀嗒声*/
void Click()
{
    sound(CLICK);
    delay(CLICKDELAY);
    nosound();
}

/*高声报时*/
void  HighBeep()
{
    sound(HEBEEP);
    delay(BEEPDELAY);
    nosound;
}

/*低声报时*/
void LowBeep()
{
    sound(LOWBEEP);
}

/*按任意角度画多边形*/
void DrawPoly(int *data,int angle,int color)
{
    int usedata[8];
    float sinang,cosang;
    int i;
    sinang=sin((float)angle/180*3.14);
    cosang=cos((float)angle/180*3.14);
    for(i=0;i<8;i+=2)
    {
        usedata[i]  =CENTERX+ cosang*data[i]-sinang*data[i+1]+.5;
        usedata[i+1]=CENTERY+sinang*data[i]+cosang*data[i+1]+.5;
    }
    setfillstyle(SOLID_FILL,color);
    fillpoly(4,usedata);
}

/*画表盘*/
void DrawClock(struct time *cutime)
{
    int ang;
    float hourrate,minrate,secrate;
    
    setbkcolor(BLACK);
    cleardevice();
    setcolor(WHITE);
    
    /* 画刻度*/
    for(ang=0;ang<360;ang+=90)
    {
        DrawPoly(Mrk_1,ang,WHITE);
        DrawPoly(Mrk_2,ang+30,WHITE);
        DrawPoly(Mrk_2,ang+60,WHITE);
    }
    secrate=(float)cutime->ti_sec/60;
    minrate=((float)cutime->ti_min+secrate)/60;
    hourrate=(((float)cutime->ti_hour/12)+minrate)/12;
    ang=hourrate*360;
    DrawPoly(HourHand,ang,YELLOW);/*画时针*/
    ang=minrate*360;
    DrawPoly(MiHand,ang, GREEN);/*画分针*/
    ang=secrate*360;
    DrawPoly(SecHand,ang, RED);/*画秒针*/
}
main()
{
    int gdriver=EGA,
        gmode=EGAHI;
    int curpage;
    struct time curtime ,newtime ;
    initgraph(&gdriver,&gmode,"c:\\tc");
    setbkcolor(BLUE);
    cleardevice();
    gettime(&curtime);
    curpage=0;
    DrawClock(&curtime);
    while(1)
    {
        if(kbhit())
            break; /*按任意键退出*/
        gettime(&newtime); /*检测系统时间*/
        if(newtime.ti_sec!=curtime.ti_sec)/*每1秒更新一次时间*/
        {
            if(curpage==0)
                curpage=1;
            else
                curpage=0;
            curtime=newtime;
            /*设置绘图页*/
            setactivepage(curpage);
            /*在图页上画表盘*/
            DrawClock(&curtime);
            /*设置绘图页为当前可见页*/
            setvisualpage(curpage);
            /*0分0秒高声报时*/
            if(newtime.ti_min==0&&newtime.ti_sec==0)
                HighBeep();
            /* 59分55至秒时低声报时*/
            else if(newtime.ti_min==59&&
                newtime.ti_sec<=59)
                LowBeep();/*其他时间只发出喀嗒声*/
            else
                Click();
        }
    }
    closegraph();
}