Question

初学者java小程序，求java大神帮我补充一下空缺代码！求如何计算 1-1/2+1/3-…+1/9-1/10的值？

import java.util.*;public class MulAdd { public static void main(String args[]){ Scanner sc = ;//接受输入 System.out.println("请输入您要求的长度"); int num = sc.nextInt(); int i; double sum1=0.0,sum2=0.0,sum; for ( ; ; ){//给定循环条件 //循环体 } System.out.println( );//输出计算结果 }}

Answer 1

import java.util.*;
public class MulAdd{
	public static void main(String[] args){
Scanner sc=new Scanner(System.in);
System.out.println("请输入您要求的长度：");
int num=sc.nextInt();
sc.close();
int i;
double sum1=0.0,sum2=0.0,sum;
for(i =1;i<=num;i++){
sum1=Math.pow(-1,i-1);
sum2=1.d/i;
sum+=sum1*sum2;
}

System.out.println(sum);
}
}

追问

sum+=sum1*sum2;
The local variable sum may not have been initialized
System.out.println(sum);
The local variable sum may not have been initialized
有错哦