Element count of an array in C++

Question

Let\'s say I have an array arr. When would the following not give the number of elements of the array: sizeof(arr) / sizeof(arr[0])?

I can

Answer 1

Use the Microsoft "_countof(array)" Macro. This link to the Microsoft Developer Network explains it and offers an example that demonstrates the difference between "sizeof(array)" and the "_countof(array)" macro.

Microsoft and the "_countof(array)" Macro