Learn C#

C# Topics

Click on a topic to expand and learn in detail.

• 1. Introduction to C#

// Hello World
using System;

class Program {
    static void Main() {
        Console.WriteLine("Hello World!");
    }
}
      

C# is an object-oriented, strongly-typed language mainly used for Windows apps, web apps, and games (Unity).

• 2. Variables & Data Types

int age = 25;
double salary = 45000.5;
string name = "Alice";
bool isStudent = true;
      

Variables store data. C# has types like int, double, string, bool, etc.

• 3. Operators

// Arithmetic
int sum = 5 + 3;

// Comparison
bool isAdult = age >= 18;

// Logical
bool flag = isAdult && isStudent;
      

Operators perform calculations, comparisons, or logical operations.

• 4. Conditions

if(age >= 18){
    Console.WriteLine("Adult");
}else{
    Console.WriteLine("Minor");
}

// Switch
switch(age){
    case 18:
        Console.WriteLine("Exactly 18");
        break;
    default:
        Console.WriteLine("Other age");
}
      

Use if-else or switch to control program flow based on conditions.

• 5. Loops

// for loop
for(int i=0; i<5; i++){
    Console.WriteLine(i);
}

// while loop
int j=0;
while(j<5){
    Console.WriteLine(j);
    j++;
}

// foreach (arrays)
string[] fruits = {"Apple","Banana","Mango"};
foreach(string fruit in fruits){
    Console.WriteLine(fruit);
}
      

Loops repeat code multiple times until a condition is met.

• 6. Functions / Methods

int Add(int a, int b){
    return a + b;
}

Console.WriteLine(Add(5,3));
      

Methods are reusable code blocks that can return values.

• 7. Object-Oriented Programming (OOP)

class Person {
    public string Name;
    public int Age;

    public void Greet(){
        Console.WriteLine("Hello " + Name);
    }
}

Person p = new Person();
p.Name = "Alice";
p.Age = 25;
p.Greet();
      

C# supports OOP concepts: Classes, Objects, Inheritance, Encapsulation, Polymorphism.

• 8. Advanced C# Topics
• Properties & Indexers
• Events & Delegates
• LINQ (Language Integrated Query)
• Exception Handling (try-catch-finally)
• Generics & Collections
• Async & Await

// Example: Exception Handling
try {
    int x = int.Parse("abc");
} catch(Exception e) {
    Console.WriteLine("Error: " + e.Message);
}