Is using const_cast for read-only access to a const object allowed?

Question

In C++ I have a function that only requires read-only access to an array but is mistakenly declared as receiving a non-const pointer:

size_t countZeroes( int         


        

Answer 1

The problem of const_cast is always the same -- it allows you to "break the rules", just like casting to and from void* -- sure you can do that, but the question is why should you?

In this case it's of course ok, but you should ask yourself why didn't you declare size_t countZeroes( const int* array, size_t count ) in the first place?

And as a general rule about const_cast:

1. It may produce hard to find bugs
2. You're throwing away the const-agreement with the compiler
3. Basically you're turning the language into a lower-level one.