#include<math.h>
#include<dos.h>
#define PI 3.1415926
//屏幕中心的坐標（640X480模式下）
#define mid_x 320
#define mid_y 240
int main()
{ int graphdriver=DETECT,graphmode;
int end_x,end_y;
struct time curtime;
float th_hour,th_min,th_sec;
initgraph(&graphdriver,&graphmode,"C:\\TC2"); //初始化VGA屏幕模式
setbkcolor(BLACK); //使用黑色的背景色
while(!kbhit(0)) //若有鍵盤輸入，則跳出，即是結束程序
{ setcolor(GREEN); //把畫筆設為綠色
circle(mid_x,mid_y,180); //鐘的外圓
circle(mid_x,mid_y,150); //鐘的內圓
circle(mid_x,mid_y,1); //畫出鐘的圓心
gettime(&curtime); //取得系統當前時間
th_sec=(float)curtime.ti_sec*0.1047197551; //把秒針的角度化為弧度，為以後繪制時方便，下同
th_min=(float)curtime.ti_min*0.1047197551+th_sec/60.0; //分針的弧度
th_hour=(float)curtime.ti_hour*0.5235987755+th_min/12.0; //時度的弧度，註意整時是12等分的，所時乘的是3.14/180*5
//計算出時針的尾的坐標（時針長70）
end_x=mid_x+70*sin(th_hour);
end_y=mid_y-70*cos(th_hour);
setcolor(RED);
line(mid_x,mid_y,end_x,end_y); //用紅色線畫出時針
//計算出分針坐標(分針長110）
end_x=mid_x+110*sin(th_min);
end_y=mid_y-110*cos(th_min);
setcolor(RED);
line(mid_x,mid_y,end_x,end_y); //用紅色畫出分針
end_x=mid_x+140*sin(th_sec);
end_y=mid_y-140*cos(th_sec);
setcolor(RED);
line(mid_x,mid_y,end_x,end_y); //同上，畫出秒針，長為140
//畫出鐘盤上的刻度，刻度長20
line(140,240,160,240); //9點對應的大刻度
line(320,60,320,80); //12點對應的大刻度
line(500,240,480,240); //3點的刻度
line(320,420,320,400); //6點的刻度
line(410,395.7,400,378.4); //5點
line(475.7,330,458.4,320); //4點
line(475.7,150,458.4,160); //2點
line(410,84.3,400,101.6); //1點
line(230,84.3,240,101.6); //11點
line(164.3,150,181.6,160); //10點
line(164.3,330,181.6,320); //8點
line(230,395.7,240,378.4); //7點
sleep(BLUE); //這裏應該是打錯，停止壹秒，應為sleep(1000)
cleardevice(); //清除屏幕上的顯示
}
closegraph(); //關閉VGA屏幕，即返回文本方式
return 0;
}