Write a function that adds two numbers. You should not use + or any arithmetic operators.

sum_without_arithmatic.cpp

int add_no_arithm(int a, int b) {
    if (b == 0) return a;
    int sum = a ^ b; // add without carrying
    int carry = (a & b) << 1; // carry, but don’t add
    return add_no_arithm(sum, carry); // recurse
}