/*
 * test.c
 *
 *  Created on: Feb 28, 2020
 *      Author: cdamian
 *
 *
 *
 *      calculul lui PI
 *      4x(1/1 - 1/3 + 1/5 - 1/7 ...)
 */



#include<stdio.h>
int main(){
	int i, n;
	int semn = +1;

	float pi = 0;

	printf("dati n: ");
	scanf("%d", &n);

	for(i = 1; i <=n ; i = i + 2){

		pi = pi + semn / (float) i;
		semn = semn * (-1);

	}

	pi *= 4;

	printf("pi = %f", pi);

	return 0;
}