Fibonacci 1.0

Using Visual Studio and C# we will build a Universal Windows Platform application that generates numbers from the Fibonacci sequence.

Info

In mathematics, the Fibonacci numbers form a sequence defined recursively as follows: start with 0 and 1, and each subsequent term is the sum of the previous two. The first Fibonacci numbers are: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, …

• Source: Wikipedia

Start

Launch Visual Studio. Create a new project via File > New > Project or use the shortcut Ctrl + Shift + N. In the dialog choose: Visual C# > Windows Universal > Blank App (Universal Windows). Name the project Fibonacci 1.0. From Solution Explorer open MainPage.xaml and MainPage.xaml.cs. If you don't see Solution Explorer, open it from View > Solution Explorer or use Ctrl + W, S.

MainPage.xaml

The MainPage.xaml file contains the user interface markup written in XAML. Copy (Ctrl+C) and paste (Ctrl+V) the fragment below into your application.

<!-- User Interface (UI): Fibonacci 1.0 -->
<StackPanel Background="Pink" Padding="50">
        
        <!-- Title -->
        <TextBlock Text="Fibonacci 1.0" FontSize="40" />

        <!-- Limit -->
        <TextBlock Text="Limit" Margin="0 10 0 10" FontSize="20" />
        <TextBox Name="boxLimit" FontSize="20" Text="1000" />
        <Button Content="Generate" Margin="0 10 0 10" Padding="20 10 20 10" FontSize="20"  Click="Button_Click" />
        
        <!-- Numbers -->
        <ListBox Name="boxNumbers"  Height="400" FontSize="20" />

</StackPanel>

Design view (XAML) in Visual Studio while developing the application:

Fig. 1.26. UI design view

MainPage.xaml.cs

The MainPage.xaml.cs file contains the business logic written in C#. Copy (Ctrl+C) and paste (Ctrl+V) the fragment below into your application.

// Business Logic (BL): Fibonacci 1.0
public sealed partial class MainPage : Page
{
        // Collection
        private ObservableCollection<int> numbers = new ObservableCollection<int>();

        // Constructor
        public MainPage()
        {
            this.InitializeComponent();
            boxNumbers.ItemsSource = numbers;
        }

        // Button Click Event Handler
        private void Button_Click(object sender, RoutedEventArgs e)
        {
            numbers.Add(1);
            numbers.Add(1);
            int limit = int.Parse(boxLimit.Text);
            int a = 1, b = 1, c = a + b;
            while (c < limit)
            {
                numbers.Add(c);
                a = b;
                b = c;
                c = a + b;
            }
        }
}

Business logic (C#) view in Visual Studio while developing the application:

Fig. 1.27. Business logic view

Demo

Start the app via Debug > Start Debugging or press F5.

Fig. 1.28. Universal app that generates numbers from the Fibonacci sequence.