C# Overview - MSDN Documentation

Welcome to C#

C# (pronounced "C sharp") is a modern, object-oriented, and type-safe programming language developed by Microsoft within the .NET initiative. It combines the productivity of a rapid application development language with the power and flexibility of a compiled language. C# is designed for building a wide variety of applications on the .NET platform, from desktop and web applications to mobile apps, games, and enterprise-level services.

This document provides a foundational understanding of C#, its key features, and how it is used to develop powerful software solutions.

Key Features of C#

Object-Oriented Programming (OOP): C# fully supports OOP principles like encapsulation, inheritance, and polymorphism, enabling developers to create modular, reusable, and maintainable code.
Type-Safe: C# is a type-safe language, meaning that the compiler enforces strict type checking at compile time, helping to prevent common errors and improving code reliability.
Component-Oriented: C# promotes component-based development, allowing developers to build and integrate reusable software components.
Modern Language Constructs: Features like LINQ (Language Integrated Query), asynchronous programming (async/await), and pattern matching make C# a powerful and expressive language.
Garbage Collection: Automatic memory management through garbage collection reduces the burden on developers to manually allocate and deallocate memory.
Extensive Class Library: The .NET Framework and .NET Core provide a rich set of pre-built libraries and APIs for various tasks, accelerating development.

Getting Started with C#

To start writing C# code, you'll need the .NET SDK. You can download it from the official .NET download page.

Here's a simple "Hello, World!" program to get you started:

Program.cs

                    using System;

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

You can compile and run this code using the .NET CLI:

dotnet new console -o MyHelloWorldApp
cd MyHelloWorldApp
dotnet run

Core Concepts

Variables and Data Types

C# is statically typed, meaning you must declare the type of a variable. Common data types include:

int (integers)
double (floating-point numbers)
bool (true/false values)
string (text)
char (single characters)

Variables.cs

                    int count = 10;
double price = 99.99;
bool isActive = true;
string message = "Welcome!";
                

Control Flow

C# provides standard control flow statements:

if, else if, else for conditional execution.
for, while, do-while, foreach for loops.
switch for multi-way branching.

Classes and Objects

As an object-oriented language, C# uses classes as blueprints for creating objects. Objects encapsulate data (fields or properties) and behavior (methods).

Classes.cs

                    public class Dog
{
    public string Name { get; set; }
    public string Breed { get; set; }

    public void Bark()
    {
        Console.WriteLine($"{Name} says Woof!");
    }
}

// Usage:
Dog myDog = new Dog { Name = "Buddy", Breed = "Golden Retriever" };
myDog.Bark();
                

Methods

Methods are blocks of code that perform a specific task. They can accept parameters and return values.

Namespaces

Namespaces are used to organize code and prevent naming conflicts. The using directive allows you to access types within a namespace.

The .NET Ecosystem

C# is the primary language for the .NET platform, which includes:

.NET Core / .NET 5+: A modern, cross-platform, high-performance framework for building web, IoT, and cloud applications.
ASP.NET Core: A high-performance, open-source framework for building modern web applications and services.
Xamarin: For building native iOS, Android, and Windows applications with C# and .NET.
Unity: A popular game development platform that uses C# for scripting.

The .NET ecosystem is constantly evolving, with frequent updates and new features being released.

Further Learning

This overview provides a glimpse into the world of C#. To dive deeper, explore these resources: