Example of C++ GUI Application

We will be using the following tools for the below programs:

Qt Library: The GUI library for our program.
Qt Designer: An interactive GUI template designer for Qt.
Qt Creator: IDE for Qt GUI Applications

Now, we will look at real cases for GUI programming with C++ and Qt. We are going to develop a basic “Hello World” application a button and when the button is clicked, a dialog box will appear with “Hello World” text written on it. We will implement it using these steps:

Step 1: Creating a Qt Project

We will open the Qt Creator and create a new project of type “Qt Widget Application”. Enter the name, select the location and you are good to go. The Qt creator will create the project with all the required files.

Step 2: Designing the Window

We will then open the file mainWindow.ui. This file contains the UI of the application. We will add one text label using the designer that just opened.

Now our files will contain the following code:

mainWindow.h

C++

#ifndef MAINWINDOW_H 
#define MAINWINDOW_H 
  
#include <QMainWindow> 
  
QT_BEGIN_NAMESPACE 
namespace Ui { class MainWindow; } 
QT_END_NAMESPACE 
  
class MainWindow : public QMainWindow 
{ 
  Q_OBJECT 
  
public: 
  MainWindow(QWidget *parent = nullptr); 
  ~MainWindow(); 
  
private: 
  Ui::MainWindow *ui; 
}; 
#endif // MAINWINDOW_H 

main.cpp

C++

#include "mainwindow.h" 
  
#include <QApplication> 
  
int main(int argc, char *argv[]) 
{ 
  QApplication a(argc, argv); 
  MainWindow w; 
  w.show(); 
  return a.exec(); 
} 

mainWindow.cpp

C++

#include "mainwindow.h" 
#include "./ui_mainwindow.h" 
  
MainWindow::MainWindow(QWidget *parent) 
  : QMainWindow(parent) 
  , ui(new Ui::MainWindow) 
{ 
  ui->setupUi(this); 
} 
  
MainWindow::~MainWindow() 
{ 
  delete ui; 
} 

mainWindow.ui

XML

<?xml version="1.0" encoding="UTF-8"?> 
<ui version="4.0"> 
 <class>MainWindow</class> 
 <widget class="QMainWindow" name="MainWindow"> 
  <property name="geometry"> 
   <rect> 
    <x>0</x> 
    <y>0</y> 
    <width>800</width> 
    <height>600</height> 
   </rect> 
  </property> 
  <property name="windowTitle"> 
   <string>MainWindow</string> 
  </property> 
  <widget class="QWidget" name="centralwidget"> 
   <widget class="QLabel" name="label"> 
    <property name="geometry"> 
     <rect> 
      <x>260</x> 
      <y>140</y> 
      <width>81</width> 
      <height>71</height> 
     </rect> 
    </property> 
    <property name="text"> 
     <string>Hello World</string> 
    </property> 
   </widget> 
  </widget> 
  <widget class="QMenuBar" name="menubar"> 
   <property name="geometry"> 
    <rect> 
     <x>0</x> 
     <y>0</y> 
     <width>800</width> 
     <height>22</height> 
    </rect> 
   </property> 
  </widget> 
  <widget class="QStatusBar" name="statusbar"/> 
 </widget> 
 <resources/> 
 <connections/> 
</ui> 

Notice that mainWindow.ui is written in XML. It is because Qt writes its UI files in XML.

Step 4: Build and Run

We can build and run the Qt project in Qt creator using a single click.

Output

Introduction to GUI Programming in C++

In C++, Graphical User Interface (GUI) programming is important in modern application development where users have nice graphics for them to work with. Although C++ is commonly linked with system programming and game writing, it can be an excellent alternative to GUI writing. In this article, we will discuss GUI programming in C++, some popular GUI libraries for C++, and how to create a basic GUI application in C++.

Prerequisites: Fundamentals of C++, C++ OOPs, Some GUI Library.

Tags:

#Geeks Premier League 2023 #C++ #Geeks Premier League #CPP

Popular GUI Libraries for C++

Advantages of GUI Applications