OOP in Dart - Classes, Inheritence

flutter-tutorial-part-01-dart-primer-OOP.dart

//  Define main function
void main() {
   
//  04. CLASSES  ============================
  print('\n04. CLASSES: \n------------------------------');
  
  User userOne = User('ancilla',30);
  print(userOne.username);
  print(userOne.age);
  
  User userTwo = User('victor',26);
  print(userTwo.username);
  print(userTwo.age);
  
  userOne.login();
  userTwo.login();
  
  // super class (child class) - Inheritance
  SuperUser userThree = SuperUser('leest', 35);
  print(userThree.username);
  print(userThree.age);
    
  userThree.login();
  userThree.publish();
  
  
  // throws Error: Compilation failed.
  // userTwo.publish();
}

//   Define a Class outside the main function
class User {
  
  String username;
  int age;
  
  User(String username, int age) {
    this.username = username;
    this.age = age;
  }
  
  void login() {
    print( this.username + ' has logged in!');
  }
  
}

//  Define a super (child) class - SuperUser
class SuperUser extends User {
  
  SuperUser(String username, int age): super(username, age);
  
  void publish() {
    print( this.username + ' has published!' );
  }
  
}