#include <stdio.h>
#include <math.h>

void Midpoint_Circle(double Xc, double Yc, double R);
void Draw_Circle (double P, double Xc, double Yc, double X, double Y);

int main () {
	double Xc, Yc, R;
	printf("Please Enter circle's center point coordinates, and radius\n");
	scanf ("%lf %lf %lf\n", &Xc, &Yc, &R);
	printf ("Calculating Circle border points for center (%lf, %lf) and radius %lf\n", Xc, Yc, R);
	Midpoint_Circle (Xc, Yc, R);
	return 0;
} 

void Midpoint_Circle(double Xc, double Yc, double R) {
	double X = 0;
	double Y = R; 
	double P = 1 - R; 
	Draw_Circle(P, Xc, Yc, X, Y); 
	while (X < Y) {
		if (P < 0) {
			P = P + 2*X + 1; 
		}
		else {
			P = P + 2*X + 1 - 2*Y; 
			Y = Y - 1;
		}
		X = X + 1;

		Draw_Circle(P, Xc, Yc, X, Y); 
	}
}



void Draw_Circle (double P, double Xc, double Yc, double X, double Y) {
	printf ("Decision Parameter P %lf\n", P);
	printf ("%lf  %lf\n", Xc + X, Yc +Y); 
	printf ("%lf  %lf\n", Xc - X, Yc +Y); 
	printf ("%lf  %lf\n", Xc + X, Yc - Y); 
	printf ("%lf  %lf\n", Xc - X, Yc - Y); 
	printf ("%lf  %lf\n", Xc + Y, Yc + X); 
	printf ("%lf  %lf\n", Xc - Y ,Yc - X); 
	printf ("%lf  %lf\n", Xc + Y, Yc - X); 
	printf ("%lf  %lf\n", Xc - Y, Yc - X);
}