package com.zsh;import java.util.Scanner;publicclassqiuhe{publicstatic Scanner input =newScanner(System.in);publicstaticvoidmain(String[] args){int x =2, y =1;double sum =0;for(int i=0;i<=20;i++){sum = sum +(double)x/y;x = x ^ y;y = x ^ y;x = x ^ y;x = x + y;}System.out.println("前二十項相加之和為:"+sum);}}