Math.pow（）无法正常工作？

Question

this is the code i made, can someone explain me why the output stays 0.0?

(I was trying to make a program that converts binary to decimal, and i know that this can be easily accomplished in java in other ways)

    package main;

    import java.util.Scanner;

    public class Class1 {

        public static void main(String[] args)
        {
            Scanner scanner = new Scanner(System.in);
            String input = scanner.nextLine();
            int length = input.length();
            double output=0.0;
            String reverse = new StringBuffer(input).reverse().toString();

            for (int i=0; i==length; i+=1){
                switch(reverse.charAt(i)){
                case '1': output = (output + (Math.pow(2, i)));break;
                case '0': break;
                }
            }
            System.out.println(output);
        }
    }

Answer 1

Unless length == 0 , that for loop never executes.

You might well mean something like:

for (int i=0; i<length; i+=1){

Also, there is no need to use Math.pow(2, i) - you can use 1 << i and keep it all as an integer.