Parallel programming final exam 1st question. C program that calcullate pi number in a basic way.

calculatePi.c

/*
	Paralel Programlama Final Soruları
	Soru 1)	Argüman olarak n sayısını alan ve geriye pi sayısını döndüren C fonksiyonunu yazınız.
	[email protected]
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

double calculatePi(int n) {
	double piSum = 0.0;

	for (int i = 0; i <= n; i++)
		if (i % 2 == 0)
			piSum += (1.0 / pow(4, i)) * (2.0 / (4.0 * i + 2.0) + 1 / (4.0 * i + 3.0) + 2.0 / (4.0 * i + 1.0));
		else
			piSum += (-1.0 / pow(4, i)) * (2.0 / (4.0 * i + 2.0) + 1 / (4.0 * i + 3.0) + 2.0 / (4.0 * i + 1.0));

	return piSum;
}

double calculatePiRecursive(int n) {

	if (n < 0)
		return 0.0;

	if (n % 2 == 0)
		return (1.0 / pow(4, n)) * (2.0 / (4.0 * n + 2.0) + 1 / (4.0 * n + 3.0) + 2.0 / (4.0 * n + 1.0)) + calculatePiRecursive(n - 1);
	else 
		return (-1.0 / pow(4, n)) * (2.0 / (4.0 * n + 2.0) + 1 / (4.0 * n + 3.0) + 2.0 / (4.0 * n + 1.0)) + calculatePiRecursive(n - 1);
}

int main(int argc, char* argv[]) {
	printf("%lf\n", calculatePi(500));
	system("PAUSE");
	return 0;
}