MSDN Documentation

Step 1: Project Setup

Let's create a new console application project. Open your terminal or command prompt and navigate to your desired project directory. Then, run the following command:

dotnet new console -n MySecondApp
cd MySecondApp

This command creates a new console application project named MySecondApp and navigates you into its directory.

Step 2: Understanding the Project Structure

Inside your MySecondApp directory, you'll find a few key files:

• MySecondApp.csproj: The project file that defines your project's properties, dependencies, and build settings.
• Program.cs: The main entry point for your application.

Open Program.cs in your favorite code editor. You should see a simple "Hello, World!" program similar to this:

// Program.cs
namespace MySecondApp
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello, World!");
        }
    }
}

Step 3: Adding Functionality - User Input

Let's modify the program to ask the user for their name and then greet them personally.

Replace the contents of Program.cs with the following code:

// Program.cs
using System;

namespace MySecondApp
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Welcome to My Second .NET App!");
            Console.Write("Please enter your name: ");
            string? userName = Console.ReadLine(); // The '?' makes userName nullable

            if (!string.IsNullOrEmpty(userName))
            {
                Console.WriteLine($"Hello, {userName}! Nice to meet you.");
            }
            else
            {
                Console.WriteLine("Hello there! It's nice to meet you.");
            }

            Console.WriteLine("Press any key to exit.");
            Console.ReadKey();
        }
    }
}

Explanation:

• using System;: Imports the System namespace, which contains essential classes like Console.
• Console.Write(): Displays text without adding a newline at the end.
• Console.ReadLine(): Reads a line of text from the console input and returns it as a string. We've used a nullable string (`string?`) to indicate that it might be null.
• !string.IsNullOrEmpty(userName): A common check to ensure the user actually entered something.
• String interpolation ($"{variable}"): A convenient way to embed variable values directly into strings.
• Console.ReadKey(): Waits for the user to press any key before the application exits.

Step 4: Running Your Application

Save the changes to Program.cs. Now, from your terminal within the MySecondApp directory, run the application using the following command:

dotnet run

You should see the welcome message, followed by a prompt for your name. Enter your name and press Enter to see the personalized greeting.

Step 5: Organizing Code with Methods

As your applications grow, it's good practice to break down functionality into smaller, reusable methods. Let's refactor our code to use a separate method for greeting.

Modify Program.cs as follows:

// Program.cs
using System;

namespace MySecondApp
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Welcome to My Second .NET App!");
            string? userName = GetUserName();
            GreetUser(userName);

            Console.WriteLine("Press any key to exit.");
            Console.ReadKey();
        }

        static string? GetUserName()
        {
            Console.Write("Please enter your name: ");
            return Console.ReadLine();
        }

        static void GreetUser(string? name)
        {
            if (!string.IsNullOrEmpty(name))
            {
                Console.WriteLine($"Hello, {name}! Nice to meet you.");
            }
            else
            {
                Console.WriteLine("Hello there! It's nice to meet you.");
            }
        }
    }
}

Explanation:

• We've created two new static methods: GetUserName() and GreetUser().
• GetUserName() is responsible for prompting the user and returning their input.
• GreetUser() takes the name as an argument and handles the greeting logic.
• The Main method now orchestrates these calls, making it cleaner and easier to understand.

Run dotnet run again to test the refactored code. The output should be the same.