在Java中从十进制转换为二进制

Question

So I have code that will convert a decimal number to binary. I use a recursive algorithm for it, however I cannot seem to get it to do what I want. Here is the code:

import java.util.*;

public class binaryAddition {

    public static int toBinary(int a){


        int bin = 0;
        int remainder = 0;
        if(a >= 1){
            toBinary(a/2);
            bin = (a%2);
        }

        return bin;


    }

    public static void main(String[] args){

        System.out.println(toBinary(3));
        System.out.print(toBinary(3));
    }
}

So I want to to return the binary solution so that I can save it as a variable in my main method. However, my current output would only give me that last digit of the binary number. I used the number 3 just as a test case and I get 1 as an output for both print and println methods. Why is that, and how can I fix it?

Many Thanks!

Answer 1

For a start, you might want to have toBinary return a String , not an int . Then you must use the result of it when you recurse. So you might write, inside your if ,

bin = toBinary(a / 2) + (a % 2);

assuming, of course, that toBinary returns String .

If you don't do this, then you're just throwing away the result of your calculation.

Answer 2

The code is discarding the results of the recursive calls.

Do something with the result of toBinary in the method.

Answer 3

Just Do it Like i have Done .

 public static void main(String[] args) 
{
    int n, count = 0, a;
    String x = "";
    Scanner s = new Scanner(System.in);
    System.out.print("Enter any decimal number:");
    n = s.nextInt();
    while(n > 0)
    {
        a = n % 2;
        if(a == 1)
        {
            count++;
        }
        x = x + "" + a;
        n = n / 2;
    }
    System.out.println("Binary number:"+x);
    System.out.println("No. of 1s:"+count);
}