Write a program to draw a circle using Bresenham’s circle drawing algorithm.

#include<iostream.h>

#include<conio.h>

#include<graphics.h>

void drawCircle(int x, int y, int xc, int yc);

void main()

{

                int gd = DETECT, gm;

                int r, xc, yc, pk, x, y;

                initgraph(&gd, &gm, "c:\\turboc3\\bgi");

                cout<<"\n

                Enter the values for center x and y\n";

                cin>>xc>>yc;

                cout<<"Enter the radius of circle\n";

                cin>>r;

                pk = 3 - 2*r;

                x=0; y = r;

                drawCircle(x,y,xc,yc);

                while(x < y)

                {

                                if(pk <= 0)

                                {

                                                pk = pk + (4*x) + 6;

                                                drawCircle(++x,y,xc,yc);

                                }

                                else

                                {

                                                pk = pk + (4*(x-y)) + 10;

                                                drawCircle(++x,--y,xc,yc);

                                }

                }

                getch();

                closegraph();

}

void drawCircle(int x, int y, int xc, int yc)

{

                putpixel(x+xc,y+yc,WHITE);

                putpixel(-x+xc,y+yc,WHITE);

                putpixel(x+xc, -y+yc,WHITE);

                putpixel(-x+xc, -y+yc, WHITE);

                putpixel(y+xc, x+yc, WHITE);

                putpixel(y+xc, -x+yc, WHITE);

                putpixel(-y+xc, x+yc, WHITE);

                putpixel(-y+xc, -x+yc, WHITE);

}