text: /**
   * @file
   * @brief Compute the greatest common denominator of two integers using
   * *iterative form* of
   * [Euclidean algorithm](https://en.wikipedia.org/wiki/Euclidean_algorithm)
   *
   * @see gcd_recursive_euclidean.cpp, gcd_of_n_numbers.cpp
   */
  #include <iostream>
  #include <stdexcept>
  
  /**
   * algorithm
   */
  int gcd(int num1, int num2)
  {
    if (num1 <= 0 | num2 <= 0)
    {
      throw std::domain_error("Euclidean algorithm domain is for ints > 0");
    }
    
    if (num1 == num2)
    {
      return num1;
    }
    
    int base_num = 0;
    int previous_remainder = 1;
    
    if (num1 > num2)
    {
      base_num = num1;
      previous_remainder = num2;
    }
    else
    {
      base_num = num2;
      previous_remainder = num1;
    }
    
    while ((base_num % previous_remainder) != 0)
    {
      int old_base = base_num;
      base_num = previous_remainder;
      previous_remainder = old_base % previous_remainder;
    }
    
    return previous_remainder;
  }
  
  /**
   * Main function
   */
  int main()
  {
    std::cout << "gcd of 120,7 is " << (gcd(120, 7)) << std::endl;
    
    try
    {
      std::cout << "gcd of -120,10 is " << gcd(-120, 10) << std::endl;
    }
    catch (const std::domain_error &e)
    {
      std::cout << "Error handling was successful" << std::endl;
    }
    
    std::cout << "gcd of 312,221 is " << (gcd(312, 221)) << std::endl;
    std::cout << "gcd of 289,204 is " << (gcd(289, 204)) << std::endl;
    return 0;
  }
  