#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
main()
{
int gd=DETECT,gm;
int xcentre=200,ycentre=200,r,x,y;
initgraph(&gd,&gm,"C:\\TC\\BGI");
printf("enter the radius");
scanf("%d",&r);
for(x=-r;x<=r/2;x++)
{
y=sqrt((r*r)-(x*x));
putpixel(x+xcentre,y+ycentre,RED);
putpixel(x+xcentre,-y+ycentre,BLUE);
}
for(x=-r/2;x<=r;x++)
{
y=sqrt((r*r)-(x*x));
putpixel(x+xcentre,y+ycentre,GREEN);
putpixel(x+xcentre,-y+ycentre,YELLOW);
}
for(x=-r;x<=r/2;x++)
{
y=sqrt((r*r)-(x*x));
putpixel(x+xcentre,y+ycentre,BLACK);
putpixel(x+xcentre,y+ycentre,YELLOW);
}
for(x=-r/2;x<=r;x++)
{
y=sqrt((r*r)-(x*x));
putpixel(x+xcentre,y+ycentre,WHITE);
putpixel(x+xcentre,-y+ycentre,GREEN);
}
getch();
}