array allocaton size

From: Keith S. (false_at_ntlworld.com)
Date: 06/25/04 

Date: Fri, 25 Jun 2004 11:17:51 +0100

This may be a dumb question, but I've searched the FAQ
and can't find an obvious answer...

Let's say I have a class e.g.

class fred
{
  public:

  int x;
  int y;
};

then I create an array of fred:

freds = new fred[2];

Now, I'd expect to have allocated 8 bytes * 2 i.e. 16 bytes.
However, if I step through the code with a debugger I see
that operator new is getting called with a size of 20 bytes.
Why is this? What's the extra 4 bytes coming from?

The platform is VC++ .NET 2003 in debug mode if it makes any
difference...

- Keith

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