Dart Inheritance and Constructors Tutorial Guide

Understanding inheritance and constructors in Dart is crucial for writing clean, maintainable, and reusable code. In object-oriented programming, inheritance allows one class to acquire properties and methods from another, while constructors are special functions used to create instances of classes.

This tutorial will guide you through the concepts of inheritance and constructors in Dart with simple, beginner-friendly examples.

Why Use Inheritance?

Inheritance promotes code reuse and modular design. It helps create a hierarchy between classes, such as parent and child relationships. Dart supports single inheritance, which means a class can inherit from only one superclass.

Understanding Constructors

Constructors in Dart are used to initialize class objects. Dart provides default constructors, named constructors, and allows constructor chaining via super() for inheritance.

Example Code:

// Parent Class
class Animal {
  String name;

  // Constructor
  Animal(this.name);

  void sound() {
    print('$name makes a sound');
  }
}

// Child Class inheriting Animal
class Dog extends Animal {
  String breed;

  // Constructor with super()
  Dog(String name, this.breed) : super(name);

  @override
  void sound() {
    print('$name barks');
  }
}

void main() {
  Dog myDog = Dog('Buddy', 'Golden Retriever');
  myDog.sound(); // Output: Buddy barks
}

This example shows how the Dog class inherits from Animal, overrides the sound() method, and calls the superclass constructor using super(name).

For a deeper dive into Dart OOP principles, visit the official Dart documentation.