class

Learn to define classes with class.

The class keyword

In Dart a class is defined with the class keyword. Example: class User { }. Inside the curly braces you write properties and methods.

A class is a blueprint for objects. It holds data (instance variables) and behavior (methods). You can create as many instances of a class as you need.

To create an instance, call the class name like a function: var u = User();. This runs the class constructor and returns a new object. Class names start with an uppercase letter in Dart; this is a convention.

Class members

A class has two kinds of members: instance variables hold data; methods define behavior. Example: class User { String name; void describe() { ... } }.

Reach instance variables with a dot: u.name. Call methods the same way: u.describe(). The dot means 'member of the instance'.

This is how access works from outside the class. Inside the class's own methods you can refer to members directly: name or this.name. this is the topic of a later lesson.

Exercise Define a User class

Define a User class whose String name property starts as 'Ayşe'. Inside main create an instance with User() and print the name with print(u.name).

Show example solution

class User {
  String name = 'Ayşe';
}

void main() {
  var u = User();
  print(u.name);
}

Test yourself

The class skeleton

class User {
  // özellikler buraya
}

void main() {
  var u = ____();
}

Show answer

class User {
  // özellikler buraya
}

void main() {
  var u = User();
}

Match the class parts

class

Class declaration
User

Class name
{}

Class body
u.name

Property access
How does a class name start?
- Lowercase
- Uppercase
- Underscore
- Digit
Show answer

Uppercase — Dart class names start with an uppercase letter.

Next lesson: Constructor

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