# How to Find Prime Number in Window Store App

In this article I explain how to determine if a specific number is a prime number or not. We all know that a number that can only be divided by one or itself is called a prime number. But implementing in a program the determination of whether a number is prime is not simple. That is why I have written some simple logic for determining prime numbers in an app.

Use the following procedure to create the prime number finder app.

Step 1

First of all you have to create a New Window Store Application, as in:

• Open Visual Studio 2012
• "File" -> "New" -> "Project..."
• Choose Template: "Visual C#" -> "Window Store app"
• "Blank App (XAML)" then rename the application.

Step 2

Now the project will be opened; go into the Solution Explorer and choose "MainPage.Xaml" designing and "MainPage.Xaml.cs" to write the business logic.

Step 3

Now I have written the simple XAML code In "Mainpage.Xaml"; see:

<Page

x:Class="prime_app.MainPage"

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

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

xmlns:local="using:prime_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="46*"/>

<RowDefinition Height="44*"/>

<RowDefinition Height="37*"/>

<RowDefinition Height="48*"/>

<RowDefinition Height="593*"/>

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

<ColumnDefinition Width="79*"/>

<ColumnDefinition Width="188*"/>

<ColumnDefinition Width="416*"/>

</Grid.ColumnDefinitions>

<TextBlock Text="Check wether Number is Prime or not" FontFamily="Arial" FontSize="15" FontWeight="ExtraBold" Grid.Column="1" Grid.Row="0" Foreground="Red"  ></TextBlock>

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

<TextBox x:Name="textbox1" Grid.Column="1" Grid.Row="1" Width="200" Height="32" HorizontalAlignment="Left" VerticalAlignment="Top" Margin="166,0,0,0"/>

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

<TextBlock x:Name="text2" FontSize="15" FontFamily="Arial" FontWeight="ExtraBold" Grid.Column="1" Grid.Row="2" Foreground="Red" Margin="166,0,60,0" RenderTransformOrigin="-1.369,0.135" />

<Button x:Name="Button1" Grid.Column="1" Grid.Row="3" Background="Yellow" Foreground="Red" Width="151" Height="43" Content="Click" FontSize="20" FontWeight="ExtraBold" Margin="165,0,0,0" VerticalAlignment="Top" RenderTransformOrigin="-0.266,-0.119" Click="Button1_Click" />

</Grid>

</Page>

Step 4

Write the C# code in the "Mainpage.Xaml.cs" page; see:

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;

namespace prime_app
{

public sealed partial class MainPage : Page
{

public MainPage()
{

this.InitializeComponent();
}

{
}

private void Button1_Click(object sender, RoutedEventArgs e)
{

int num = Convert.ToInt32(textbox1.Text);

for (int i = 2; i <= num - 1; i++)
{

if (num % i == 0)
{
text2.Text =
"Not a Prime Number";

break;
}

if (i == num - 1)
{
text2.Text =
"Prime Number";
}
}

if (num == 1 || num == 2)
{
text2.Text =
"Prime Number";
}
}
}
}

Step 5