Compiling and Generating helloworld

Procedure

1. Use PuTTY to log in to the server as the root user.
2. Create a helloworld directory.

   mkdir helloworld

3. Go to the helloworld directory.

   cd helloworld

4. Create a helloworld.cpp file and edit it.
   1. Create and open the helloworld.cpp file.

      vi helloworld.cpp

   2. Press i to enter insert mode and add the following information:

      #include<QApplication>
      #include<QLabel>
      int main(int argc,char *argv[])
       {
      QApplication app(argc,argv);
      QLabel *label=new QLabel("helloworld!");
      label->show();
      return app.exec();
       }

   3. Press Esc, type :wq!, and press Enter to save the file and exit.
5. Perform the compilation.

   qmake -project
   qmake
   make

   If the following error information is displayed after running the make command, add QT+=widgets to the end of the helloworld.pro file.

   

   

   helloworld.pro is the a.pro file generated by running the qmake -project command. a indicates the directory name.

6. Run helloworld.

   ./helloworld