C# Programming Basics

C# (pronounced “C Sharp”) is a modern, object-oriented programming language developed by Microsoft. It’s widely used for building desktop apps, web apps, mobile apps, and games (especially with Unity).

1.Your First C# Program

A simple C# program looks like this:

using System;

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

Explanation:

• using System; → imports basic functionality (like Console for input/output).
• class Program → defines a class (the building block of C# programs).
• static void Main(string[] args) → the entry point of every C# application.
• Console.WriteLine() → prints text to the screen.

2.Variables & Data Types

C# is strongly typed, meaning each variable has a specific data type.

int age = 25;             // Integer
double price = 19.99;     // Decimal numbers
char grade = 'A';         // Single character
string name = "Alice";    // Text
bool isStudent = true;    // True/False

3.Operators

int a = 10, b = 5;

Console.WriteLine(a + b); // 15 (addition)
Console.WriteLine(a - b); // 5  (subtraction)
Console.WriteLine(a * b); // 50 (multiplication)
Console.WriteLine(a / b); // 2  (division)
Console.WriteLine(a % b); // 0  (remainder)

4.Control Flow

If-Else

int age = 18;

if (age >= 18)
    Console.WriteLine("You are  an adult.");
else
    Console.WriteLine("You are a minor.");  
                                        

Switch

string day = "Monday";

switch (day)
{
    case "Monday":
        Console.WriteLine("Start of the week!");
        break;
    case "Friday":
        Console.WriteLine("Weekend is near!");
        break;
    default:
        Console.WriteLine("Another day.");
        break;
}

5.Loops

For Loop

for (int i = 1; i <= 5; i++)
{
    Console.WriteLine("Number: " + i);
}

While Loop

int count = 1;
while (count <= 5)
{
    Console.WriteLine("Count: " + count);
    count++;
}

6.Arrays

string[] fruits = { "Apple", "Banana", "Cherry" };

foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

7.Methods (Functions)

static int AddNumbers(int x, int y)
{
    return x + y;
}

Console.WriteLine(AddNumbers(5, 10)); // Output: 15

8.Classes & Objects

class Car
{
    public string Brand;
    public int Year;

    public void Start()
    {
        Console.WriteLine(Brand + " is starting!");
    }
}

// Using the class
Car myCar = new Car();
myCar.Brand = "Toyota";
myCar.Year = 2020;
myCar.Start(); // Toyota is starting!

Summary:

• C# is object oriented and strongly typed.
• Key concepts: variables, operators, control flow, loops, arrays, methods, and classes.
• It’s powerful for games, apps, and enterprise software.