Question

Is it better to do:

const int MY_CONST = 20; // global constant in the program
class A {
    // uses MY_CONST all over the class implementation and definition
}

or this?

const int MY_CONST = 20; // global constant in the program
template<int my_const>
class A {
    //uses my_const only and never MY_CONST
};

//A<MY_CONST> used later in the program

Is one of these pattern better than the other? why?
thanks

Answer 1

The second solution is sensible if it makes sense to instantiate e.g. A<MY_CONST + 1>, or A<0>, or any other value than MY_CONST. If, however, A is strictly designed to be used with the one value, then you don’t gain anything from that. In that respect the first solution gives you everything you need.