Question

This is an assignment question from school: Create a recursive method called toBinary that takes a single integer as a parameter and outputs the equivalent in binary.

Here’s my code:

import java.util.*;
class MethodAssign6{
static void toBinary(int a){
    if(a==0){
        System.out.print("theArrayOrStringIWant");
    }
    else{
        System.out.println(a%2);
        toBinary(a/2);
    }
}
public static void main(String[]args){
    toBinary(24);
}
}

As you can see, I have no idea how to create an array to hold all the a%2 values when the question only wants me to have a single integer as a parameter. Anyone please help me I would appreciate very much.

Answer 1

I think you’re on the right track—but your current method will print the number out backwards. Try doing the recursive call and then printing:

static void toBinary(int a){
    if(a!=0) {
        toBinary(a/2);
        System.out.print(a%2);
    }
}

You could also get a similar effect using a String:

static String toBinary(int a){
    if(a==0) {
        return "";
    }
    else {
        return toBinary(a/2) + (a%2);
    }
}

public static void main(String[]args){
    System.out.println(toBinary(24));
}