How to reliably get size of C-style array?

Question

How do I reliably get the size of a C-style array? The method often recommended seems to be to use sizeof, but it doesn\'t work in the foo function

Answer 1

An array expression will have its type implicitly converted from "N-element array of T" to "pointer to T" and its value will be the address of the first element in the array, unless the array expression is the operand of either the sizeof or address-of (&) operators, or if the array expression is a string literal being used to initialize another array in a declaration. In short, you can't pass an array to a function as an array; what the function receives is a pointer value, not an array value.

You have to pass the array size as a separate parameter.

Since you're using C++, use vectors (or some other suitable STL container) instead of C-style arrays. Yes, you lose the handy shorthand syntax, but the tradeoff is more than worth it. Seriously.