delete[] Array of characters [duplicate]

Question

Possible Duplicate:
delete[] supplied a modified new-ed pointer. Undefined Behaviour?

Let's say I've allocated a handful of characters using new char[number].

Will it be possible to delete only a few end characters (something like delete[] (charArray + 4);, which will supposedly de-allocate all of characters except for the first four)?

I read that some implementations' new[] store the number of objects allocated before the array of objects so that delete[] knows how many objects to de-allocate, so it's probably unsafe to do what I'm asking...

Thanks.

EDIT:

Is manually deleting the unwanted end bytes using separate delete statements a safe way to do what I'm asking?

Answer 1

No, you have to delete[] exactly the same pointer you get back with new[].

Answer 2

You can't delete a specific segment of an array.

If you're just operating on C strings, you can set a character to \0 and any functions that operate on the string will stop there, as C strings are null-terminated.

If you actually need to free up that memory, the closest you can get would be to make a new, smaller array, copy the elements over, and delete[] the old array.

char* TenCharactersLong = new char[10];
// ...
char* FirstFiveCharacters = new char[5];
for (std::size_t Index = 0; Index < 5; Index++)
{
    FirstFiveCharacters[Index] = TenCharactersLong[Index];
}
delete[] TenCharactersLong;