#include<graphics.h>/*加入c圖形庫*/
#include<math.h>/*數學庫*/
#include<conio.h>/*鍵盤控制*/
void Line(int x0,int y0,int x1,int y1,int value)/*從坐標(x0,y0)到(x1,y1)畫顏色為value的直線*/
{
int x;
float dx,dy,m,y;
dx=x1-x0;dy=y1-y0;m=dy/dx;y=y0;
for(x=x0;x<=x1;x++)
{
	putpixel(x,(int)(y+0.5),value);/*畫點*/
	y=y+m;
	if(getch()==17)exit();/*讀入鍵盤按鍵*/
}
}
void main()
{
int i,driver,mode;
driver=DETECT;/*初始化顯示模式參數*/
initgraph(&driver,&mode,"..\\bgi");/*初始化顯示為默認驅動的640*480、16色模式*/
printf("Press any key to continue except 'Ctrl+Q' to quit.\n");
Line(100,100,500,400,15);/*設置畫線起始點*/
closegraph();/*關閉圖形模式*/
}