In this article you can learn about Factorial Numbers. So first of all let us understand what a Factorial Number is. Then I will describe Factorial Numbers in programming terms.

Factorial Number

A number is a Factorial Number that is the product of a given positive integer multiplied by all lesser positive integers. The Symbol of Factorial is "!".

Example: Number 5!=5*4*3*2*1

Use the following procedure to create the Factorial app.

Step 1

First of all you have to create a New Windows Store Application.

new-windows-store-app.jpg

Step 2

Write the following XAML code in "Mainpage.Xaml" (that is available in Solution Explorer):

<Page

x:Class="Factorial_app.MainPage"

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

xmlns:local="using:Factorial_app"

xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

mc:Ignorable="d">

<Grid Background="Blue">

<Grid.RowDefinitions>

<RowDefinition Height="38*"/>

<RowDefinition Height="23*"/>

<RowDefinition Height="31*"/>

<RowDefinition Height="32*"/>

<RowDefinition Height="37*"/>

<RowDefinition Height="607*"/>

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

<ColumnDefinition Width="282*"/>

<ColumnDefinition Width="62*"/>

<ColumnDefinition Width="339*"/>

</Grid.ColumnDefinitions>

<TextBlock Text="Get The Factorial Of Number" FontFamily="Arial" FontSize="15" FontWeight="ExtraBold" Foreground="Red" Grid.ColumnSpan="3" Grid.Row="1" TextAlignment="Center" ></TextBlock>

<TextBlock Text="Enter Number:" FontFamily="Arial" FontSize="15" FontWeight="ExtraBold" Foreground="Red" Grid.Column="1" Grid.Row="2"></TextBlock>

<TextBox x:Name="Textbox1" Width="150" Height="32" VerticalAlignment="Top" Grid.Column="2" Grid.Row="2" HorizontalAlignment="Left" Grid.RowSpan="2" />

<TextBlock Text="Factorial is:" FontFamily="Arial" FontSize="15" FontWeight="ExtraBold" Foreground="Red" Grid.Column="1" Grid.Row="3"></TextBlock>

<TextBlock x:Name="text2" FontFamily="Arial" FontSize="15" FontWeight="ExtraBold" Foreground="Red" Grid.Column="2" Grid.Row="3" Margin="5,0,661,0" Height="32" VerticalAlignment="Bottom" />

<Button Content="Click" Click="Button1_click" Grid.Column="2" Grid.Row="4" FontSize="15" Foreground="Red" Background="Yellow" Width="137" Height="39" VerticalAlignment="Top" Grid.RowSpan="2" />

</Grid>

</Page>

Step 3

Now write the following C# code for the button within "Mainpage.Xaml.cs":

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using Windows.Foundation;

using Windows.Foundation.Collections;

using Windows.UI.Xaml;

using Windows.UI.Xaml.Controls;

using Windows.UI.Xaml.Controls.Primitives;

using Windows.UI.Xaml.Data;

using Windows.UI.Xaml.Input;

using Windows.UI.Xaml.Media;

using Windows.UI.Xaml.Navigation;

namespace Factorial_app

{

public sealed partial class MainPage : Page

{

public MainPage()

{

this.InitializeComponent();

}

protected override void OnNavigatedTo(NavigationEventArgs e)

{

}

private void Button1_click(object sender, RoutedEventArgs e)

{

int num = Convert.ToInt32(Textbox1.Text);

int fact = 1;

for (int i = num; i > 0; i--)

{

fact = fact * i;

}

text2.Text = fact.ToString();

}

}

}

Step 4

Now Run Your app.

run-factorial-app.jpg

output-of-factorial-app.jpg