Re: Strcut padding?

From:

wahaha <zhang.yeliang@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 23 Feb 2008 18:10:30 -0800 (PST)

Message-ID:

<5a77548c-af5e-470d-8985-894918f8e1d4@s12g2000prg.googlegroups.com>

On Feb 22, 6:22 pm, diligent.sn...@gmail.com wrote:

On Feb 23, 2:58 am, "webinfin...@gmail.com" <webinfin...@gmail.com>
wrote:

#include <iostream>
#include <string>

using namespace std;

int main() {
  char t1;
  struct t2{
    char x;
  };

  cout << sizeof(t1) << " " << sizeof(t2) << endl;

  typedef char& x1;
  struct x2{
    x1 x;
  };

  cout << sizeof(x1) << " " << sizeof(x2) << endl;

}

output:
1 1
1 4

Can anybody tell me why the size of x2 is 4? Why it's not 1?

Hello,

This question was answered here:http://groups.google.com/group/alt.comp.lang.learn.c-c++/browse_threa...
(in particular Karl Heinz Buchegger's answer)

It all comes down to the fact that the implementation of a reference
is compiler dependent, and a compiler may use a pointer to implement
reference semantics (which probably explains size of 4 bytes).

Regards.

Thank you. But how it will explain sizeof(char&) = 1 but sizeof(struct
x2) = 4?