// C++ Program to add two numbers without using arithmetic operator.
// bitadd.cpp
// Built with : g++ -o bitadd -std=c++11 -Wall -O3 bitadd.cpp
#include <cstddef>
#include <cstdint>
#include <vector>
#include <utility>
#include <iostream>
#include <fstream>
#include <sstream>

// uncomment one of these
// typedef int32_t  my_int;
typedef int64_t  my_int;

my_int Add(my_int x, my_int y) 
{ 
    // Iterate till there is no carry   
    while (y != 0) { 
        // carry now contains common set bits of x and y 
        my_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 required sum
        y = carry << 1; 
    } 
    return x; 
}

using my_list_type = std::vector< std::pair<my_int, my_int> >;
  
int main() 
{
    my_list_type ops = {
       {           0,   1 },
       {           1,  -1 },
       {          69, -42 },
       {          42,  69 },
       {         -42,  69 },
       {         -42, -69 },
       {         256, 512 },
       {   123456789,   1 },
       {  2147483647,   1 },
       { -2147483648,   1 }
   };
   my_int sum0, sum1;
   std::cout << "sizeof my int = " << sizeof(my_int) << "\n";
   for (const auto& c : ops) {
      sum0 = c.first + c.second;
      sum1 = Add(c.first, c.second);
      if (sum0 != sum1) { std::cout << "oops!\n"; }
      std::cout << c.first << " + " << c.second << " = " << sum0 << " (" << sum1 << ")\n";
   }

   return 0; 
}