C# Multiple Classes and Objects

In C#, you can define multiple classes in a program and create multiple objects from those classes. This helps organize code and model real-world relationships.

🔹 Multiple Classes in One Program

class Student
{
public string Name;
public int Age;

public void Display()
{
Console.WriteLine($"Student: {Name}, Age: {Age}");
}
}

class Teacher
{
public string Name;
public string Subject;

public void Display()
{
Console.WriteLine($"Teacher: {Name}, Subject: {Subject}");
}
}

class Student

{

public string Name;

public int Age;

public void Display()

{

Console.WriteLine($"Student: {Name}, Age: {Age}");

}

class Teacher

{

public string Name;

public string Subject;

public void Display()

{

Console.WriteLine($"Teacher: {Name}, Subject: {Subject}");

}

🔹 Creating Objects from Multiple Classes

🔹 Multiple Objects from Same Class

✔ Each object stores separate data.

🔹 One Class Using Another Class

class Engine
{
public int Power = 120;
}

class Car
{
public string Brand = "BMW";
public Engine engine = new Engine();

public void Show()
{
Console.WriteLine($"{Brand} - {engine.Power} HP");
}
}




Car car = new Car();
car.Show();

class Engine

{

public int Power = 120;

}

class Car

{

public string Brand = "BMW";

public Engine engine = new Engine();

public void Show()

{

Console.WriteLine($"{Brand} - {engine.Power} HP");

}

Car car = new Car();

car.Show();

✔ This is called composition.

🔹 Multiple Classes in Separate Files

Best practice:

All classes can still work together if they are in the same namespace.

🔹 Using Namespace

🔹 Real-World Example

✔ Models real-life relationships.

🔹 Common Mistakes

❌ Forgetting object creation
❌ Accessing members without object
❌ Circular dependencies

🔹 Summary

✔ Multiple classes organize code
✔ Multiple objects represent real data
✔ Objects can interact with each other
✔ Use namespaces for clarity

C# Multiple Classes and Objects