package com.itranswarp.learnjava;

/**
 * for练习
 */
public class Main {

	public static void main(String[] args) {
		double quraterPi = 0;
		boolean sign = true;
		for (int i = 1; i < 100000; i += 2,sign = !sign) {
			double j = sign ? i : -i;
			quraterPi += 1 / j;
		}
		double pi = quraterPi * 4;
		System.out.println(pi);
	}

}