View source for Development/Tutorials/KDE2/KHello/Tutorial 1

==Description==
This is, as far as I know, the simplest possible KDE program.
==Source code==
The source code is very simple:
<code cppqt n>
/************* khello.cc *******************/
#include <kapp.h>
#include <kmainwindow.h>

int main( int argc, char **argv )
{
  KApplication a( argc, argv, "khello" );
  KMainWindow *w = new KMainWindow();
  w->setGeometry(100,100,200,100);

  a.setMainWidget( w );
  w->show();
  return a.exec();
}
/************* end of file *****************/
</code>
== Explaining the code==
Here is the commands explained:
<code cppqt>
#include <kapp.h>
#include <kmainwindow.h>
</code>
The kapp.h file contain some basic code needed by all programs, and the kmainwindow.h file contains the class which should be used for all main windows in KDE programs.
<code cppqt>
KApplication a(argc, argv);
KMainWindow *w = new KMainWindow();
</code>
Create a KApplication object and a KMainWindow object. The KApplication object will contain all the basic code our program needs, and the KMainWindow object will be our main window.
<code cppqt>
w->setGeometry(100,100,200,100);
</code>
Move and resize the window. It is moved to coordinates (100, 100), and the size are changed to 200x100 (width x height).
<code cppqt>
a.setMainWidget( w );
</code>
Our program needs to know where to find the main window.
<code cppqt>
w->show();
</code>
Make the main window visible.
<code cppqt>
return a.exec();
</code>
Execute the program.
==Compiling==
'''[on linux where KDEDIR and QTDIR contain the paths to where KDE and Qt are installed respectively]'''

'''[FreeBSD 5.x users may omit the <tt>-ldl</tt>]'''
 g++ -c -I$KDEDIR/include -I$QTDIR/include -fno-rtti khello.cc
 g++ -L$KDEDIR/lib -L$QTDIR/lib -lkdeui -lkdecore -lqt -ldl -o khello khello.o