How do I check if a template parameter is a power of two?

Question

I want to create a structure that allocates statically an array of 2^N bytes, but I don\'t want the users of this structure to specify this size as the exponent

Answer 1

These days, with constexpr and the bit twiddling hacks you can just

constexpr bool is_powerof2(int v) {
    return v && ((v & (v - 1)) == 0);
}