Int cannot be converted to binary string

Question

import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {

    String a = "10";
    String b = "11";

    int a0 = Integer.parseInt(a, 2);
    int b1 = Integer.parseInt(b, 2);

    int product = a0 * b1;
    Integer.toString(product);
    int result = Integer.parseInt(product);
    System.out.print(result);
    }
}

I've tried all the methods I've seen in stackoverflow and none of them work in my case. I can convert the binary to base10, but can't convert it back.

Answer 1

Internally, everything is binary. But visually, binary is just one representation for human consumption. Other primary ones are octal, decimal, or hex. But the default when printing integers is to print them in the decimal representation. If you want a binary string, just do:

    String a = "10";
    String b = "11";

    int a0 = Integer.parseInt(a, 2);
    int b1 = Integer.parseInt(b, 2);

    int product = a0 * b1;
    String result = Integer.toBinaryString(product);
    System.out.print(result);

Prints

110

Also note that you can assign ints a value in binary representation.

int a = 0b11;
int b = 0b10;