Question

I have a function

static bool Validate(const char& letter, string& aWord)

I need to invoke it

Validate(letter, aWord); // where aWord is const

What is the correct way to const_cast in this case?

Answer 1

If you are absolutely sure that the function does not modify the string, you can do this:

Validate (letter, const_cast<std::string &>(aWord));

However, a safer thing to do, albeit it an unnecessary copy if the signature could hypothetically be changed to const, would be to copy the string and pass the copy.

std::string copyOfAWord = aWord;
Validate (letter, copyOfAWord);

If it does change something, your copy would have the results instead, but it would break your logic in the first place.