#include <iostream>
enum class COLOR
{
    Blue,
    Red,
    Green,
    Purple,
    First=Blue,
    Last=Purple
};

extern const COLOR COLORS[(int)COLOR::Last+1];
const COLOR COLORS[] = {COLOR::Blue, COLOR::Red, COLOR::Green, COLOR::Purple};

std::ostream& operator<<(std::ostream& o, COLOR x) {
	return o << std::underlying_type<COLOR>::type(x);
}


int main() { 
    for(auto c : COLORS) {
        std::cout << c << '\n';
    }
    return 0;
}