如何利用Java語言計算1+1/3-1/5+1/7-1/9+1/11...

如何利用Java語言計算1+1/3-1/5+1/7-1/9+1/11…

package com.mtons.mblog.leetcode;

/**
 * 如何利用Java語言計算1+1/3-1/5+1/7-1/9+1/11...
 */
public class SumNum {

    public static double sum(int n){
        double sum = 1.00;
        for (int i=2;i<=n;i++){
            if(i % 2==0){
                sum = sum + (1.0/(i*2-1));
            }else{
                sum = sum - (1.0/(i*2-1));
            }

        }
        return sum;
    }

    //以下爲測試代碼
    public static void main(String[] args) {
        System.out.println(sum(6));

        double dd = 1.0+1.0/3-1.0/5+1.0/7-1.0/9+1.0/11;
        System.out.println(dd);
        System.out.println(1.0/3);
        System.out.println(1.0/5);
        System.out.println(1.0/7);
        System.out.println(1 % 2);
    }



}