Java program to add two number without using addition operator.

package demo;
import java.util.Scanner;
public class Addition
{
 public static void main(String[] args) 
 {
  int a, b;
  int sum;
  Scanner sc = new Scanner(System.in);
  System.out.print("Enter any two integers: ");
  a = sc.nextInt();
  b = sc.nextInt();
  sum = a - ~b - 1;
  System.out.print("Sum of two integers: " + sum);
 }
}

Output:
Enter any two integers: 20
50
Sum of two integers: 70
BUILD SUCCESSFUL (total time: 10 seconds)



Algorithm:

In c ~ is 1's complement operator. This is equivalent to:  
~a = -b + 1
So, a - ~b -1
= a-(-b + 1) + 1
= a + b – 1 + 1
= a + b