CareerCup

package main

import "fmt"

func Sum(a, b int) int {
	res := a ^ b
	y := a & b << 1
	for y > 0 {
		a = res
		res = res ^ y
		y = a & y << 1
	}
	return res
}

func main() {
	fmt.Println(Sum(10, 20)) // Output: 30
}

I would just write the simple logic here :

int Add(int x, int y){
    while(y!=0){
        int carry = (x&y)<<1;
        x=x^y;
        y=carry;
    }
    return x;
}

handles all cases easy ans simple

#include<bits/stdc++.h>
using namespace std;
int main()
{
int a,b;
cin>>a>>b;
while(b!=0)
{
int carry= a&b;
a = a ^ b;
b = carry<<1;
}
cout<< a<<endl;;
}

#include<stdio.h>

int Add(int x, int y)
{
// Iterate till there is no carry
while (y != 0)
{
// carry now contains common set bits of x and y
int carry = x & y;

// Sum of bits of x and y where at least one of the bits is not set
x = x ^ y;

// Carry is shifted by one so that adding it to x gives the required sum
y = carry << 1;
}
return x;
}