Creating a composite type from two enum classes, ready for STL map

Question

I would like to create a composite type out of two enum classes.

enum class Color {RED, GREEN, BLUE};
enum class Shape {SQUARE, CIRCLE, TRIANGLE};

         


        

Answer 1

That's a good question, but you don't actually need the number of Color to compare them :

friend bool operator< (const Object &lhs, const Object &rhs) {
    if(lhs.color > rhs.color) {
        return false;
    }
    if(lhs.color < rhs.color) { 
        return true;
    }
    return lhs.shape < rhs.shape;
}