Initializing a constexpr with a const, — int vs float

Question

I\'m wondering why the integer ii is initiallized at compile time, but not the float ff here:

int main() {
  const int i = 1;
  con         


        

Answer 1

In C++ constant integers are treated differently than other constant types. If they are initialized with a compile-time constant expression they can be used in a compile time expression. This was done so that array size could be a const int instead of #defined (like you were forced in C):

(Assume no VLA extensions)

const int s = 10;
int a[s];          // OK in C++