Class

🧱 What is a Class in C#?

A class is one of the fundamental building blocks of Object-Oriented Programming (OOP).

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📌 Definition

• A class is a user-defined data type.

• It is a collection of data members (variables) and member functions (methods).

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🔹 Data Members

These are the variables declared inside a class.

✅ Example

int a;
string s;

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🔹 Member Functions

These are the methods defined inside a class.

✅ Example

void display()
{
}

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⚙️ Key Points About Class

• A class acts as a blueprint for creating objects.

• It contains:

  • Data (variables)

  • Behavior (methods)

• Classes help in organizing code using encapsulation.

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🔐 Access Specifier

• A class is generally declared as public so it can be accessed from anywhere.

• However, it can also be private, internal, or protected depending on requirement.

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🧱 Creating an Instance of a Class

To use a class, we create an instance (object) using the new keyword.

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✅ Example

using System;

class Program
{
    static void Main()
    {
        Program p1 = new Program();
        // Program → class
        // p1 → instance of the class
    }
}

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🧠 Key Takeaways

• Class = Blueprint

• Object/Instance = Actual implementation

• Data members → store data

• Member functions → define behavior

• new keyword is used to create an instance

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This concept is the foundation of OOP and is essential for understanding advanced topics like inheritance, polymorphism, and abstraction.