Getting Started with C#

What is C#?

C# (pronounced "C-Sharp") is a modern, object-oriented programming language developed by Microsoft as part of the .NET framework. It combines the power of C++ with the simplicity of Visual Basic, making it an excellent choice for beginners and experienced developers alike.

Key Features

C# offers several powerful features that make it a popular choice for software development:

• Type Safety: Strong typing system prevents many common programming errors
• Memory Management: Automatic garbage collection handles memory allocation and deallocation
• Object-Oriented: Full support for classes, inheritance, polymorphism, and encapsulation
• Cross-Platform: Runs on Windows, macOS, and Linux with .NET Core/.NET 5+

Your First C# Program

Let's start with the classic "Hello, World!" program:

using System;

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

Breaking Down the Code

Let's examine each part of this program:

using System;  // Imports the System namespace

The using System; directive allows us to use classes from the System namespace without fully qualifying them.

namespace HelloWorld  // Defines a namespace
{
    // Code goes here
}

Namespaces help organize code and prevent naming conflicts.

class Program  // Defines a class
{
    // Class members go here
}

Every C# program must have at least one class.

static void Main(string[] args)  // Entry point of the program
{
    Console.WriteLine("Hello, World!");  // Prints to console
}

The Main method is where program execution begins.

Modern C# Syntax (C# 9+)

With newer versions of C#, you can write even simpler programs:

using System;

Console.WriteLine("Hello, World!");

This top-level program feature eliminates the need for explicit namespace, class, and Main method declarations for simple programs.

Setting Up Your Environment

Installation Options

npm install dotnet --version

To get started with C#, you'll need:

1. .NET SDK: Download from dotnet.microsoft.com
2. Code Editor: Visual Studio, Visual Studio Code, or JetBrains Rider
3. Terminal/Command Prompt: For running dotnet commands

Creating a New Project

# Create a new console application
dotnet new console -n MyFirstApp

# Navigate to the project directory
cd MyFirstApp

# Run the application
dotnet run

Basic Syntax Rules

C# follows specific syntax rules that you should remember:

Case Sensitivity

C# is case-sensitive, meaning Variable and variable are different identifiers.

Semicolons

Most statements in C# must end with a semicolon (;).

Console.WriteLine("This statement ends with a semicolon");  // Correct
Console.WriteLine("This statement also needs one")  // Error: missing semicolon

Curly Braces

Code blocks are enclosed in curly braces { }.

if (condition)
{
    // Code block
    Console.WriteLine("Inside the if block");
}

Comments

Comments help document your code and are ignored by the compiler:

// This is a single-line comment

/*
   This is a multi-line comment
   that can span multiple lines
*/

/// <summary>
/// This is an XML documentation comment
/// Used for generating API documentation
/// </summary>
public class MyClass
{
    // Class implementation
}

Next Steps

Now that you understand the basics of C# syntax and structure, you're ready to explore:

• Variables and Data Types: Learn about storing and manipulating data
• Control Structures: Master if statements, loops, and decision-making
• Methods and Functions: Organize your code into reusable blocks
• Object-Oriented Programming: Dive deep into classes and objects

Each of these topics will build upon what you've learned here, gradually expanding your C# programming skills.