Classes and Instances

Classes and Instances

In this lesson — part of Objects and Classes — you'll learn classes and instances in C# and why it matters in real work.

Why it matters

Classes bundle data and behavior together — the core of object-oriented design.

Key ideas

• Classes and instances
• Fields and methods
• Constructors
• Encapsulation

In practice

Here's how it looks in idiomatic C#:

public class Counter
{
    private int _count;              // field
    public void Increment() => _count++;  // method
    public int Value => _count;      // read-only property
}

var c = new Counter();
c.Increment();
Console.WriteLine(c.Value);  // 1

C# note: Idiomatic C# exposes state through properties (get/set) rather than public fields, keeping fields private and conventionally underscore-prefixed.

Try it yourself

Exercise: In C#, write a Bank Account class with deposit and withdraw methods.

Recap

You now understand classes and instances and can apply it in C#. Mark this lesson complete and continue to the next one.