Const vs constexpr

[DanM]

constexpr everywhere you can, otherwise const.

constexpr > const > nothing

See here on the difference:

Could we put const at the top of the file and why constexpr?

This is incorrect. constexpr means that the variable/function can be evaluated at compile time, it’s not guaranteed that it necessarily will be. Similarly const doesn’t mean it will be evaluated at run-time. const int val = 5 * 5; is a constant expression and val would be 25 and no calculation of 5*5 would be done at run-time. https://godbolt.org/z/90pTqc Also incorrect. https://godbolt.org/z/KZctLy. It’s the same if you enable optimisations or not. These examples are too trivial for the …