计算11-12+13-14......+199-1100的值

import java.util.Scanner; //计算1/1-1/2+1/3-1/4…+1/99-1/100的值 public class TestDemo1 { public static double sumN(int n){ double sum=0.0; int flg=1; for (int i = 1; i <100 ; i++) { sum+=flg*1.0/i; flg=-flg; }return sum; } public static void main(String[] args) { Scanner scanner=new Scanner(System.in); int n=scanner.nextInt(); double ret=sumN(n); System.out.println(ret); } }