C# Programming Lecture Notes

Introduction

• Overview of C# programming language.
• Flexible language used for console apps, web services, games, etc.
• Average salary for a C# developer: $63,000/year.

Getting Started with C#

IDE

• Recommended IDE: Visual Studio Community.
• Installation steps:
  • Download Visual Studio and follow installation procedures.
  • Select .NET desktop development package.
  • Choose color theme (dark preferred).

Creating a New Project

• Select File -> New Project.
• Choose C# Console Application.
• Name project (e.g., "My First Program").
• Customize font size in Visual Studio settings.

Basics of C# Programming

"Hello World" Program

• Default program displays "Hello World".
• Main method as the entry point for the program.
• Compile and run by clicking the green play button.

Output Methods

• Use Console.WriteLine() for output.
• Change text output by editing contents within quotes.
• Example:
  • Console.WriteLine("I like pizza");

Console Customization

• Adjust console font and size via properties.

Variables in C#

Declaration and Initialization

• Declare variables and assign values:
  • int x = 123;
• Use descriptive variable names (e.g., int age = 21;).

Data Types

• Common data types: int, double, bool, char, string.
• Example of using bool:
  • bool isAlive = true;

Comments

• Use single-line comments // and multi-line comments /*...*/.

Control Flow

If Statements

• Check conditions using if-else statements: if (age >= 18) Console.WriteLine("You're signed up!"); else Console.WriteLine("Must be 18+");

Switch Statements

• Efficient alternative to multiple else-if statements.
• Example: switch (day) { case "Monday": Console.WriteLine("It's Monday"); break; }

Loops in C#

While Loops

• Continue executing code while a condition is true: while (name == "") { Console.WriteLine("Enter your name:"); name = Console.ReadLine(); }

For Loops

• Execute a block of code a finite number of times: for (int i = 0; i < 10; i++) { Console.WriteLine(i); }

Methods in C#

Defining Methods

• Methods for reusable code: public void SayHello() { Console.WriteLine("Hello!"); }

Overloading Methods

• Same name but different parameters.

Object-Oriented Concepts

Classes and Objects

• Class as a blueprint for creating objects.
• Objects as instances of a class.
• Example: class Dog { public void Bark() { Console.WriteLine("Woof!"); } }

Inheritance

• Child classes inherit fields and methods from parent classes.
• Example: class Animal { ... } class Dog : Animal { ... }

Polymorphism

• Objects can be treated as instances of their parent class.

Interfaces

• Define what methods a class must implement.
• Example: interface IFlyable { void Fly(); }

Generics

• Create classes and methods that operate on any data type. public class GenericList<T> { ... }

Exception Handling

• Use try-catch blocks to handle exceptions: try { // Code that may throw an exception } catch (SpecificException e) { // Handle exception }

Properties and Access Modifiers

• Use properties with getters and setters for encapsulation: public int Speed { get; set; }

Auto-Implemented Properties

• Shortcuts for properties without extra logic.

Enums

• Define named constants: enum Days { Sunday, Monday, Tuesday }

Lists

• Dynamically sized collections of objects: List<string> fruits = new List<string>();

Multi-threading

• Create multiple threads to perform tasks concurrently: Thread thread1 = new Thread(new ThreadStart(MethodName)); thread1.Start();

Summary

• Review of key concepts and tools for programming in C#.
• Emphasis on exploration and practice.