C# Programming Language Cheatsheet

If you’re a programmer navigating the vast landscape of programming languages, chances are you’ve encountered C# (pronounced C-sharp) at some point. Developed by Microsoft, C# is a powerful, versatile, and object-oriented programming language that has become a staple in the world of software development. Whether you’re a beginner or an experienced developer, having a cheatsheet handy can be incredibly valuable. This cheatsheet will serve as your quick reference guide to the essentials of C# programming.

1. Basic Syntax:

// Hello World
using System;

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

• C# is case-sensitive.
• Statements are terminated by semicolons.

2. Variables and Data Types:

// Variables and Data Types
int age = 25;
float salary = 50000.50f;
string name = "John";
char grade = 'A';
bool isStudent = true;

• C# has a rich set of data types, including integers, floating-point numbers, strings, characters, and booleans.

3. Control Flow:

// If-Else Statement
int num = 10;
if (num > 0)
{
    Console.WriteLine("Positive");
}
else if (num < 0)
{
    Console.WriteLine("Negative");
}
else
{
    Console.WriteLine("Zero");
}

• C# supports if-else statements, switch statements, while loops, do-while loops, and for loops for control flow.

4. Functions and Methods:

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

// Method
static void DisplayMessage(string message)
{
    Console.WriteLine(message);
}

• Functions are defined using the returnType functionName(parameters) syntax.
• Methods are functions defined within a class and are invoked using an instance of the class or the class itself for static methods.

5. Arrays:

// Array
int[] numbers = { 1, 2, 3, 4, 5 };

• Arrays in C# are zero-indexed.
• You can access elements using square brackets: numbers[0] returns 1.

6. Classes and Objects:

// Class
class Dog
{
    public string Breed;
    public int Age;

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

// Object
Dog myDog = new Dog();
myDog.Breed = "Labrador";
myDog.Age = 3;
myDog.Bark();

• Classes encapsulate data and behavior.
• Objects are instances of classes.

7. Exception Handling:

// Exception Handling
try
{
    // Code that might throw an exception
}
catch (Exception ex)
{
    Console.WriteLine($"An error occurred: {ex.Message}");
}
finally
{
    // Code that will always run, whether an exception occurs or not
}

• Exception handling is crucial for dealing with runtime errors and ensuring graceful program execution.

8. LINQ (Language Integrated Query):

// LINQ
var result = from num in numbers
             where num % 2 == 0
             select num;

• LINQ provides a concise way to query collections in C#.

9. Lambda Expressions:

// Lambda Expression
Func<int, int, int> add = (a, b) => a + b;
Console.WriteLine(add(3, 5)); // Outputs 8

• Lambda expressions are concise anonymous functions.

10. Asynchronous Programming:

// Asynchronous Programming
async Task<int> GetDataAsync()
{
    // Asynchronous code
    return await FetchData();
}

• C# supports asynchronous programming using the async and await keywords.

This cheatsheet covers the fundamental aspects of C# programming. Keep it handy as you dive into the world of C# development, and remember, practice is key to mastering any programming language. Happy coding!

Refer to the official documentation for more in-depth information and examples.