#include<graphics.h>/*加入c圖形庫*/
#include<math.h>/*數(shù)學庫*/
#include<conio.h>/*鍵盤控制*/
void MidpointLine(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 dy,dx,incrE,incrNE,d,x,y;
dy=y0-y1;
dx=x1-x0;
d=2*dy+dx;
incrE=2*dy;
incrNE=2*(dy+dx);
x=x0;
y=y0;
putpixel(x,y,value);/*畫點函數(shù)*/
while(x<x1)
{
	if(d<0)
	{	
	x++;
	y++;
	d+=incrNE;
	}
	else
	{
	x++;
	d+=incrE;
	}
	if(getch()==17)exit();/*讀入鍵盤按鍵*/
	putpixel(x,y,value);
}
}
void main()
{
int i,driver,mode;
driver=DETECT;/*初始化顯示模式參數(shù)*/
initgraph(&driver,&mode,"..\\bgi");/*初始化顯示為默認驅(qū)動的640*480、16色模式*/
printf("Press any key to continue except 'Ctrl+Q' to quit.\n");
MidpointLine(100,100,500,400,15);/*設置畫線起始點*/
closegraph();/*關閉圖形模式*/
}