#### Gcd Iterative Euclidean

```/**
* @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;
}
```