About include 'styles'

[tonnot]

I have seen a few distinct include sintax :

#include <QtGui/QApplication>
#include <QApplication>
#include "QtGui/QApplication"

All of them are valid ? Any explanation?

[wysota]

All of them are valid ?

Yes.

Any explanation?

The explanation is all three syntaxes are valid for C/C++.

[tbscope]

#include "A"

#include "A"

To copy to clipboard, switch view to plain text mode 

Looks for A in the source directory first, then in the other directories known by the compiler.

#include <A>

#include <A>

To copy to clipboard, switch view to plain text mode 

Does not look for A in the source directory first, but in the directories known by the compiler.

#include <A/B>

#include <A/B>

To copy to clipboard, switch view to plain text mode 

Looks for A/B in the know directories.

Edit: this is basic C++ by the way. If you look this up in google or any good book store you find tons of information about it.