package cn.edu.bjut.chapter2;

public class FractionSummation {
	public static void main(String[] args) {
		double sum = 0; 
		for (int n = 1; (1.0 / n >= 1e-5); n++) {
			if (n % 2 == 0) { // 偶数
				sum -= 1.0 / n; 
			} else { // 奇数
				sum += 1.0 / n; 
			}
		}
		System.out.println(sum);
	}
}