C# Programming Introduction

Introduction to Programming

Programming is the process of designing and building executable computer programs to perform specific tasks. Programs consist of instructions written in a **programming language** that a computer understands and executes to process inputs and generate desired outputs.

What is a Program?

A **program** is a structured sequence of instructions written in a programming language that tells a computer how to perform a particular operation. Programs range from simple scripts that display messages on a screen to complex systems managing databases, websites, and artificial intelligence.

Example: A Simple C# Program

using System;

class Program
{
    static void Main()
    {
        // Declare two numbers
        int num1 = 10;
        int num2 = 20;

        // Calculate the sum
        int sum = num1 + num2;

        // Display the result
        Console.WriteLine($"The sum of {num1} and {num2} is: {sum}");
    }
}

// Output:
// The sum of 10 and 20 is: 30
        

In this example:

• We define two **integer variables** `num1` and `num2` with values **10** and **20**.
• We compute their **sum** and store it in `sum`.
• Using **string interpolation (`$""`)**, we display the result in the console.

Evolution of Programming Languages

Programming languages have evolved significantly, from **low-level machine code** to **modern high-level languages** that enhance readability, efficiency, and reusability.

• 1940s: Early computers used **machine language** (binary code - 1s and 0s).
• 1950s: **Assembly language** introduced symbolic instructions, making programming easier.
• 1960s: High-level languages like **FORTRAN** and **COBOL** emerged for scientific and business applications.
• 1970s: **C language** was created, forming the foundation for many modern languages.
• 1980s-1990s: **Object-Oriented Programming (OOP)** languages like **C++ and Java** introduced reusability and modular design.
• 2000s-Present: **C# was introduced by Microsoft** as a modern, flexible, and efficient programming language.

Why Learn C#?

**C#** is a powerful, modern, and versatile programming language developed by **Microsoft** as part of the **.NET ecosystem**. It is widely used in software development, including **web applications, desktop apps, mobile apps, cloud computing, and game development**.

Key Advantages of Learning C#

• Cross-Platform: With **.NET Core**, C# runs on **Windows, macOS, and Linux**.
• Object-Oriented: Encourages **modular, reusable, and maintainable** code.
• Strongly Typed: Reduces errors by enforcing **strict data types**.
• Great for Enterprise Applications: Used extensively in **corporate and enterprise software development**.
• Rich Library Support: The **.NET framework** provides vast **built-in libraries** for various functionalities.
• Ideal for Game Development: C# is the primary language for **Unity**, one of the most popular game engines.
• Robust Security: Includes built-in **memory management** and garbage collection.

Features of C#

• Automatic Garbage Collection: **.NET’s runtime** handles memory allocation and deallocation.
• LINQ: **Language Integrated Query (LINQ)** allows powerful data manipulation with **database-like queries** in C#.
• Asynchronous Programming: Built-in support for **async/await** makes concurrent programming simpler.
• Interoperability: C# interacts seamlessly with **C++, F#, and JavaScript**, allowing smooth integration.
• Unified Type System: All data types derive from **System.Object**, ensuring consistency.

What is C# .NET?

C# is part of the **.NET ecosystem**, which provides a **robust runtime environment**, libraries, and tools for **developing scalable applications**. With frameworks like **ASP.NET**, C# is a dominant force in **web and cloud-based solutions**.

C# .NET Ecosystem Includes:

• ASP.NET: For building web applications.
• Blazor: Enables web applications using C# and WebAssembly.
• WinForms & WPF: For desktop applications.
• Xamarin: For cross-platform mobile app development.
• Unity: For game development.