#include<graphics.h>
void zhixian(int x0,int y0,int x1,int y1);
main()
{
int gm;
int gd;
gd=DETECT;
gm=0;
initgraph(&gd,&gm,"");
setcolor(RED);
zhixian(0,0,40,70);
getch();
}
void zhixian(int x0,int y0,int x1,int y1)
{
int a,b,d1,d2,d,x,y;
a=y0-y1,b=x1-x0,d=2*a+b;
d1=2*a,d2=2*(a+b);
x=x0,y=y0;
putpixel(x,y,RED);
while(x<x1)
{
if(d<0)
{x++,y++,d+=d2;}
else
{x++,d+=d1;}
putpixel(x,y,RED);
}
}�