b'\n_START_ARTICLE_\nGtkmm\n_START_SECTION_\nHello World\n_START_PARAGRAPH_\n//HelloWorldWindow.h#ifndef HELLOWORLDWINDOW_H#define HELLOWORLDWINDOW_H#include <gtkmm/window.h>#include <gtkmm/button.h>// Derive a new window widget from an existing one.// This window will only contain a button labelled "Hello World"class HelloWorldWindow : public Gtk::Window{_NEWLINE_  public:_NEWLINE_    HelloWorldWindow();_NEWLINE__NEWLINE_  protected:_NEWLINE_    void on_button_clicked(); //event handler_NEWLINE__NEWLINE_    Gtk::Button hello_world;};#endif_NEWLINE_//HelloWorldWindow.cc#include <iostream>#include "HelloWorldWindow.h"HelloWorldWindow::HelloWorldWindow()_NEWLINE_ : hello_world("Hello World"){_NEWLINE_    // Set the title of the window._NEWLINE_    set_title("Hello World");_NEWLINE__NEWLINE_    // Add the member button to the window,_NEWLINE_    add(hello_world);_NEWLINE__NEWLINE_    // Handle the \'click\' event._NEWLINE_    hello_world.signal_clicked().connect(_NEWLINE_        sigc::mem_fun(*this, &HelloWorldWindow::on_button_clicked));_NEWLINE__NEWLINE_    // Display all the child widgets of the window._NEWLINE_    show_all_children();}void HelloWorldWindow::on_button_clicked(){_NEWLINE_    std::cout << "Hello world" << std::endl;}_NEWLINE_//main.cc#include <gtkmm/main.h>#include "HelloWorldWindow.h"int main(int argc, char *argv[]) _NEWLINE_{_NEWLINE_    // Initialization_NEWLINE_    Gtk::Main kit(argc, argv);_NEWLINE__NEWLINE_    // Create a hello world window object_NEWLINE_    HelloWorldWindow example;_NEWLINE__NEWLINE_    // gtkmm main loop_NEWLINE_    Gtk::Main::run(example);_NEWLINE_    return 0;}'