initialize array size from another array value

Question

#include 
using namespace std; 

const int vals[] = {0, 1, 2, 3, 4}; 

int newArray[ vals[2] ]; //\"error: array bound is not an integer constant\"

         


        

Answer 1

It's possible that the value of a const expression is not even known at compile time. For example, you can initialize a constant with something returned from a function, like

const int size = rand(); // random size

So it is not that constant as you might think