#include <gtk/gtk.h>

static gint delete_event_cb(GtkWidget* w, GdkEventAny* e, gpointer data);
static void button_click_cb(GtkWidget* w, gpointer data);

int
main(int argc, char* argv[])
{
        GtkWidget* window;
        GtkWidget* button;
        GtkWidget* label;
        
        gtk_init(&argc,&argv);
        
        window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
        
        button = gtk_button_new();
        
        label = gtk_label_new("Halo Indonesia");
        
        gtk_container_add(GTK_CONTAINER(button), label);
        gtk_container_add(GTK_CONTAINER(window), button);
        
        gtk_window_set_title(GTK_WINDOW(window),"HALO");
        gtk_container_set_border_width(GTK_CONTAINER(window), 10);
        
        g_signal_connect(G_OBJECT(window),
                           "delete_event",
                           G_CALLBACK(delete_event_cb),
                           NULL);
                           
        g_signal_connect(G_OBJECT(button),
                           "clicked",
                           G_CALLBACK(button_click_cb),
                           label);
                           
        gtk_widget_show_all(window);
        
        gtk_main();
        
        return 0;
        
}

static gint
delete_event_cb(GtkWidget* w, GdkEventAny* e, gpointer data)
{
        gtk_main_quit();
        return FALSE;
}

static void
button_click_cb(GtkWidget* w, gpointer data)
{
        GtkWidget* label;
        gchar* text;
        gchar* tmp;
        
        label = GTK_WIDGET(data);
        
        gtk_label_get(GTK_LABEL(label), &text);
        
        tmp = g_strdup(text);
        
        g_strreverse(tmp);
        
        gtk_label_set_text(GTK_LABEL(label), tmp);
        
        g_free(tmp);
}