Development/Tutorials/First program

Your first program shall greet the world with a friendly "hello world", what else ? For that, we will use a KMessageBox. To get more information about the KMessageBox-Class, type "kde: kmessagebox" in your konqueror and it will redirect you to http://developer.kde.org/documentation/library/cvs-api/kdelibs-apidocs/kdeui/html/classKMessageBox.html <highlightSyntax language="cpp">

#include <QString>
#include <kapplication.h>
#include <kaboutdata.h>
#include <kmessagebox.h>
#include <kcmdlineargs.h> 

int main (int argc, char *argv[])
{
 KAboutData aboutData( "test", "test",
     "1.0", "test", KAboutData::License_GPL,
     "(c) 2006" );
 KCmdLineArgs::init( argc, argv, &aboutData );
 KApplication khello;
 KGuiItem kgi(QString("Hello"),QString(),
 QString("this is a tooltip"),
 QString("this is whatsthis"));
 KMessageBox::questionYesNo(0,"text","caption",kgi);
}

</highlightSyntax> If you set up your environment as described in Build/Unstable Version, you can compile this code with

gcc hello.cpp -o hello -I/home/kde-devel/qt-unstable/include/Qt \
-I/home/kde-devel/qt-unstable/include/Qt-Core \
-I/home/kde-devel/qt-unstable/include -I/home/kde-devel/kde/include \
-L/home/kde-devel/kde/lib \
-L/home/kde-devel/qt-unstable/lib -lkdeui -lkdecore -ldl 

and then run it with ./hello

Tip

Note: This page is about KDE 4. It isn't applicable for KDE 3 development.