Binary number system has only two symbols 0 & 1 so a binary numbers consists of only 0’s and 1’s. Before we write a program for addition, lets see how we do the addition on paper, this is shown in the diagram below: [Addition of two binary numbers]

Adding binary numbers in Java

Code:

import java.util.Scanner;
public class JavaExample {
   public static void main(String[] args)
   {
	//Two variables to hold two input binary numbers
	long b1, b2;
	int i = 0, carry = 0;

	//This is to hold the output binary number
	int[] sum = new int[10];

	//To read the input binary numbers entered by user
	Scanner scanner = new Scanner(System.in);

	//getting first binary number from user
	System.out.print("Enter first binary number: ");
	b1 = scanner.nextLong();
	//getting second binary number from user
	System.out.print("Enter second binary number: ");
	b2 = scanner.nextLong();

	//closing scanner after use to avoid memory leak
	scanner.close();
	while (b1 != 0 || b2 != 0)
	{
		sum[i++] = (int)((b1 % 10 + b2 % 10 + carry) % 2);
		carry = (int)((b1 % 10 + b2 % 10 + carry) / 2);
		b1 = b1 / 10;
		b2 = b2 / 10;
	}
	if (carry != 0) {
		sum[i++] = carry;
	}
	--i;
	System.out.print("Output: ");
	while (i >= 0) {
		System.out.print(sum[i--]);
	}
	System.out.print("\n");
   }
}

Output:

Enter first binary number: 11100
Enter second binary number: 10101
Output: 110001

Try Yourself

Built-in Method: Can you do this using Integer.parseInt(binaryString, 2)? Try it.
Different Lengths: Test the program with binary numbers of different lengths (e.g., 101 and 11).
Invalid Input: What happens if you enter 102? Add a check to validate if the input is binary.
Subtraction: Can you modify the logic to perform binary subtraction?
Brain Twister: Convert a decimal number to binary without using built-in methods.

Java Program to Add two Binary Numbers

Adding binary numbers in Java

Code:

Output:

Try Yourself

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