Cirlce Drawing using Midpoint Algorithm

MidpointCircle.cpp

#include <stdio.h>
#include <graphics.h>
#include <math.h>
int max(int a, int b) {return a > b ? a : b;}
void draw_cirlce(int, int, int, int);
int main(int argc, char const *argv[])
{
	int gd = DETECT, gm;
	initgraph(&gd, &gm, "Midpoint Circle Drawing");
	int xc = 320, yc = 240; //co-ordinates
	int r = 30; // radius
	int p = 1 - r; //initial decision
	int y = r;
	for(int x = 0; x <= y; x++) {
		if(p <= 0) {
			p = p + 2 * x + 3;
		}
		else {
			y = y - 1;
			p = p + 2 * (x - y) + 5;
		}
		draw_cirlce(xc, yc, x, y);
	}
	getch();
}
void draw_cirlce(int xc, int yc, int x, int y) {
		putpixel(xc+x,yc-y,1);
		putpixel(xc-x,yc-y,2);
		putpixel(xc+x,yc+y,3);
		putpixel(xc-x,yc+y,4);
		putpixel(xc+y,yc-x,5);
		putpixel(xc-y,yc-x,6);
		putpixel(xc+y,yc+x,7);
		putpixel(xc-y,yc+x,8);
}