Add demo file (#2)

.gitignore

@@ -54,5 +54,3 @@ dkms.conf
 # Directory
 bin/*
 
-# Sample Codes
-demo.c

demo.c

@@ -0,0 +1,56 @@
+#include "fawn.h"
+#include <stdio.h>
+
+void AddNewBtnClicked(GtkWidget *widget, gpointer data) {
+    printf("Welcome to the Fawm demo application!\n");
+}
+
+int main(int argc, char *argv[]) {
+
+    // Initialize Fawn.
+    FawnInit(argc, argv);
+
+    // Load CSS.
+    LoadCss("demo.css");
+
+    // Button widget.
+    GtkWidget *top_btn = NewButton("Add New", "add-new");
+    Action(top_btn, "clicked", AddNewBtnClicked);
+
+    // Window widget.
+    uint size[2] = {500, 200};
+    GtkWidget *header = NewHeaderBar("My Application", 1, top_btn);
+    GtkWidget *window = NewWindow("My Window", size, header, TRUE, "", TRUE);
+
+    // Alter widget.
+    GtkWidget *alter = NewAlert("Welcome!", "This is Fawn demo application", "welcome", TRUE);
+    Attach(alter, window);
+
+    // Box widget.
+    GtkWidget *box = NewBox(true, 1);
+    Attach(box, window);
+
+    // Input widget.
+    GtkWidget *input = NewInput("Enter name", "", FALSE, 25, "username", 0, 10);
+    Attach(input, box);
+
+    // Action of the big button.
+    void WelcomeMessage(GtkWidget *widget, gpointer data) {
+        char *username = GetEntryText(input, FALSE);
+        char *welcome_message = malloc(sizeof(char) * strlen(username) + 6);
+        sprintf(welcome_message, "Hello %s", username);
+        GtkWidget *welcome_window = NewWindow("Welcome", size, NULL, TRUE, "", FALSE);
+        GtkWidget *alter = NewAlert("Welcome!", welcome_message, "welcome-username", TRUE);
+        Attach(alter, welcome_window);
+    }
+
+    // Big button widget.
+    GtkWidget *big_btn = NewBigButton("Welcome Message", "Click to see the welcome message!", "bigbutton");
+    Action(big_btn, "clicked", WelcomeMessage);
+    Attach(big_btn, box);
+
+    // Render the design.
+    FawnRender();
+
+    return 0;
+}