#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
void ellips(int x,int y);
void completellipse(int r,int g,int
u,int v)
{
float s,k,e,f,x;
double p1,p2;
s=r;k=g;
e=(pow((s+.5),2));
f=(pow((k-1),2));
p2=((u*e)+(v*f)-(u*v));
ellips(s,k);
while(k>=0)
{
if(p2>0)
p2=(p2+v-(2*v*s));
else
{
p2=(p2+(2*u*(s+1))-(2*v*(k-1))+v);
s++;
}
k--;
ellips(s,k);
}
}
void main()
{
int gdriver=DETECT,gmode;
int a,b,x,y;
long u,v,p1;
initgraph(&gdriver,&gmode,"C:\\tc\\bgi::");
printf("\n enter the length of
major axis:");
scanf("\t%d",&a);
printf("\n enter the length of
minor axis:");
scanf("\t%d",&b);
x=0;
y=b;
u=pow(b,2);
v=pow(a,2);
p1=(u-(v*b)+(.25*v));
ellips(x,y);
while(2*(u*x)<=2*(v*y))
{
x++;
if(p1<0)
p1=(p1+(2*u*v)+v);
else
{
p1=(p1+(2*u*x)-(2*v*y)+u);
y--;
}
ellips(x,y);
}
completellipse(x,y,u,v);
getch();
closegraph();
}
void ellips(int x,int y)
{
putpixel(x+200,y+200,8);
putpixel(-x+200,y+200,8);
putpixel(x+200,-y+200,8);
putpixel(-x+200,-y+200,8);
}