Circle Drawing Algorithm in Computer Graphics

#include<graphics.h>

#include<stdio.h>

#include<conio.h>

#include<math.h>

#define SQUARE(x) ((x)*(x))

void drawcircle(int, int, int);

void main()

{

  int gd=DETECT,gm;

  int xc,yc,r;

  initgraph(&gd,&gm,"C:\\TC\\BGI");

  xc=getmaxx()/2;

  yc=getmaxy()/2;

  r=100;

  drawcircle(xc,yc,r);

  getch();

  closegraph();

}

void drawcircle(int xc,int yc,int r)

{

  int i,x,y,y1;

  for(i=xc-r;i<=xc+r;i++)

  {

    x=i;

    y=yc+sqrt(SQUARE(r)-SQUARE(x-xc));

    y1=yc-sqrt(SQUARE(r)-SQUARE(x-xc));

    putpixel(x,y,1);

    putpixel(x,y1,1);

    delay(100);

  }

}

//Drawing circle using polar equations

void drawcircle(int xc,int yc,int r)

{

  int x,y;

  float theta;

  const float PI=3.14;

  for(theta=0.0;theta<=360;theta+=1)

  {

    x=xc+r*cos(theta*PI/180.0);

    y=yc+r*sin(theta*PI/180.0);

    putpixel(x,y,1);

  }

}

OUTPUT:

Mid-Point Circle Drawing Algorithm >>