MSDN Documentation

Introduction to C#

Welcome to the world of C#! This guide will introduce you to the fundamental concepts and syntax of the C# programming language, empowering you to start building powerful applications on the .NET platform.

What is C#?

C# (pronounced "C sharp") is a modern, object-oriented programming language developed by Microsoft. It's designed to be a simple, general-purpose, type-safe, and object-oriented language. C# is a versatile language used for developing a wide range of applications, including:

• Web applications and services (ASP.NET)
• Desktop applications (Windows Forms, WPF)
• Mobile applications (Xamarin)
• Game development (Unity)
• Cloud services
• Internet of Things (IoT) devices

Key Features of C#

C# offers several compelling features that make it a popular choice for developers:

• Object-Oriented: Supports classes, objects, inheritance, polymorphism, and encapsulation.
• Type-Safe: The compiler checks for type compatibility, reducing runtime errors.
• Managed Code: Executed within the .NET Common Language Runtime (CLR), which provides features like automatic memory management (garbage collection).
• Component-Oriented: Designed for building reusable software components.
• Modern Syntax: Influenced by C++, Java, and other languages, making it relatively easy to learn.
• Rich Standard Library: The .NET Framework/Core provides a vast collection of pre-built classes and functionalities.

Your First C# Program: "Hello, World!"

Let's start with the traditional "Hello, World!" program. This simple program demonstrates the basic structure of a C# application.

using System;

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

Explanation:

• using System;: This line imports the `System` namespace, which contains fundamental classes like `Console`.
• public class HelloWorld: This declares a class named `HelloWorld`. In C#, all code resides within classes.
• public static void Main(string[] args): This is the entry point of the application. The program execution begins here.
  • public: An access modifier, meaning the method can be accessed from anywhere.
  • static: The method belongs to the `HelloWorld` class itself, not to any specific instance of the class.
  • void: The method does not return any value.
  • Main: The name of the entry point method.
  • string[] args: An array of strings that can be used to pass command-line arguments to the application.
• Console.WriteLine("Hello, World!");: This line uses the `WriteLine` method from the `Console` class to print the string "Hello, World!" to the console, followed by a new line.

Next Steps

Congratulations on writing your first C# program! In the next tutorials, we'll dive deeper into essential C# concepts such as variables, data types, operators, and control flow structures. Keep exploring and happy coding!