Question

Possible Duplicate:
Is it a good idea to wrap an #include in a namespace block?

// Method One
#ifndef XXX_H
#define XXX_H
#include <iostream>
#include "myhead.h"
namespace XXX
{
    /...
}
#endif

OR

// Method Two
namespace XXX
{
#ifndef XXX_H
#define XXX_H

    #include <iostream>
    #include "myhead.h"
    /...
#endif
}

When we define a new namespace XXX, should we move #include directive inside namespace or not?

Thank you

Answer 1

You must not include <iostream> inside your namespace. You will get linker errors.

I would not suggest including any headers within a namespace.

The only exception would be where you have a header which defines only extern "C" functions (and no C++ functions or classes), you can usually include that in a namespace without causing linker problems. But it is still probably not a good idea.