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.RowDefinitions>

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

</Grid.ColumnDefinitions>

</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;
using Windows.UI.Xaml.Navigation;

namespace prime_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);

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

Run your application.

Step 6

Now enter a number in the TextBox to determine if the number is prime or not.

2 Comments

Join the conversation! Your thoughts help the community grow.

Satya Prakash13y ago
Hi, Sam your logic is also true. but i have implemented more understandable code. Any one can understand this logic according to prime number definition of mathematics.
Sam Hobbs13y ago
Instead of "for (int i = 2; i <= num - 1; i++)" I think you can use "for (int i = 2; i <= num/2 - 1; i++)". And I think that if the number is not divisible by 3 then the number iterations can be correspondingly reduced. I am not a mathematician but I found something that I think says we can stop at the square root of the number.