MIDPOINT.C

#include<stdio.h>
#include<conio.h>
#include<dos.h>
#include<graphics.h>
void midPointCircleDraw(int x_centre, int y_centre, int r)
{
    int x = r, y = 0,P;
    if (r > 0)
    {
	putpixel(x+x_centre,-y+y_centre,WHITE);
	putpixel(y+x_centre,x+y_centre,WHITE);
	putpixel(-y+x_centre,x+y_centre,WHITE);
    }

    P = 1 - r;
    while (x > y)
    {
	y++;
	if (P <= 0)
	    P = P + 2*y + 1;
	else
	{
	    x--;
	    P = P + 2*y - 2*x + 1;
	}
	if (x < y)
	    break;
	putpixel(x+x_centre,y+y_centre,BLUE);
	putpixel(-x+x_centre,y+y_centre,BLUE);
	putpixel(x+x_centre,-y+y_centre,BLUE);
	putpixel(-x+x_centre,-y+y_centre,BLUE);
	if (x != y)
	{
	    putpixel(y+x_centre,x+y_centre,RED);
	    putpixel(-y+x_centre,x+y_centre,RED);
	    putpixel(y+x_centre,-x+y_centre,RED);
	    putpixel(-y+x_centre,-x+y_centre,RED);
	}
    }
}

int main()
{
    int gd = DETECT, gm;
    initgraph (&gd, &gm, "C:\\Turboc3\\BGI");
    clrscr();
    midPointCircleDraw(200,200, 50);
    midPointCircleDraw(200,200,100);
    midPointCircleDraw(200,200,150);
    getch();
    return 0;
}