MidpointEllipse

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void plot(int x,int y,int xc,int yc)
{putpixel(xc+x,yc+y,RED);
putpixel(xc+x,yc-y,RED);
putpixel(xc-x,yc+y,RED);
putpixel(xc-x,yc-y,RED);
}
void myellipse(long xc,long yc,long rx,long ry)
{long rx2=rx*rx,ry2=ry*ry,twoRx2=2*rx2,p;
long twoRy2=2*ry2,px=0,py=twoRx2*ry;
long x=0,y=ry;
p=ry2-rx2*ry+0.25*ry2;
plot(0,ry,xc,yc);
while(px<py)
{x++;
 px=px+twoRy2;
if(p<0)
p=p+px+ry2;
else
{y--;
 py=py-twoRx2;
p=p+px-py+ry2;
}
plot(x,y,xc,yc);
}
p=(ry2*(x+0.5)*(x+0.5))+(rx2*(y-1)*(y-1))-(rx2*ry2);
while(y>0)
{y--;
py=py-twoRx2;
if(p<0)
{x++;
px=px+twoRy2;
p=p+px-py-rx2;
}
else
p=p-py-rx2;
plot(x,y,xc,yc);
}
}
void main()
{
int gd=DETECT,gm;
clrscr();
initgraph(&gd, &gm, "C:\\tc\\bgi");
myellipse(200,200,10,10);
myellipse(200,200,30,30);
myellipse(200,111,10,60);
myellipse(200,289,10,60);
myellipse(112,200,60,10);
myellipse(288,200,60,10);

getch();
}