Java Program to Add Two Binary Numbers

Last Updated: 09 July, 2022

Example 1: A Java program to add two binary numbers

  public class AddBinaryNumbers1 {
    public static void main(String[] args) {
      // two binary numbers
      long binaryNum1 = 10101;
      long binaryNum2 = 10001;
      
      System.out.println("First binary number: " + binaryNum1);
      System.out.println("Second binary number: " + binaryNum2);
      
      int i = 0;
  
      // carry value which holds the carry value
      int carry = 0;
  
      // array to hold the output binary number
      int[] finalSumOutput = new int[10];
  
      while (binaryNum1 != 0 || binaryNum2 != 0) {
  
        finalSumOutput[i++] = (int) (carry + (binaryNum1 % 10 + binaryNum2 % 10) % 2);
  
        carry = (int) ((binaryNum1 % 10 + binaryNum2 % 10 + carry) / 2);
  
        binaryNum1 = binaryNum1 / 10;
        binaryNum2 = binaryNum2 / 10;
      }
      if (carry != 0) {
        finalSumOutput[i++] = carry;
      }
      --i;
  
      System.out.print("Addition of two binar numbers: ");
      // printing from the last index to 0 index.
      while (i >= 0) {
        System.out.print(finalSumOutput[i--]);
      }
    }
  }

Output

First binary number: 10101
Second binary number: 10001
Addition of two binar numbers: 100110

Example 2: A Java program to add two binary numbers using Scanner Class

  
  import java.util.Scanner;
  public class AddBinaryNumbers2 {
    public static void main(String[] args) {
      Scanner scanner = new Scanner(System.in);
      System.out.print("Enter first binary number: ");
      long binaryNum1 = scanner.nextLong();
      System.out.print("Enter second binary number: ");
      long binaryNum2 = scanner.nextLong();
      scanner.close();
      
      int i = 0;
      // carry value which holds the carry value
      int carry = 0;
      
      // array to hold the output binary number
      int[] finalSumOutput = new int[10];
      
      while (binaryNum1 != 0 || binaryNum2 != 0) {
        
        finalSumOutput[i++] = (int) (carry + (binaryNum1 % 10 + binaryNum2 % 10) % 2);
        
        carry = (int) ((binaryNum1 % 10 + binaryNum2 % 10 + carry) / 2);
        
        binaryNum1 = binaryNum1 / 10;
        binaryNum2 = binaryNum2 / 10;
      }
      if (carry != 0) {
        finalSumOutput[i++] = carry;
      }
      --i;
      
      System.out.print("Addition of two binar numbers: ");
      // printing from the last index to 0 index.
      while (i >= 0) {
        System.out.print(finalSumOutput[i--]);
      }
    }
  }

Output

Enter first binary number: 10101
Enter second binary number: 10001
Addition of two binar numbers: 100110