Sample code demonstrating Classes and Inheritance in Dart

classes-and-inheritance.dart

void main() {
  var johnny = Person('Johnny', 42)
    ..speak()
    ..name = 'Big Johnny'
    ..speak();
  
  var johnnyB = Person('Johnny', 42);
  print(johnny == johnnyB);
  
  var bob = Employee('Bob', 23, DateTime.now());
  bob.speak();
}

class Employee extends Person {
  DateTime joinDate;
  String name;
  
  Employee(this.name, int age, this.joinDate) : super(name, age);
  
  @override
  speak() {
    print('My name is $name. I joined on $joinDate.');
  }
}

class Person {
  var _name;
  var age;
  
  Person(name, age) {
    this._name = name;
    this.age = age;
  }
  
  String get name => _name;
  
  void set name(String updatedName) => _name = updatedName;
  
  bool operator ==(dynamic b) => _name == b._name && age == b.age;
  
  speak() {
    print("My name is $_name. I'm $age years old.");
  }
}