Dart intro

import 'dart:math';

const String h = 'kjddHjblwoopwedlradljljlkdfefldlkfdog dgdfgdf';

abstract class A {
  String getMessage() => 'A';
}

class B {
  String getMessage() => 'B';
}

class P {
  String getMessage() => 'P';
}

class AB extends P with A, B {}

class BA extends P with B, A {}

class CC implements P {
  
  CC(this.message, {int howMuch = 3}) {
    _val = List<int>.generate(howMuch, (index) => index + 1);
  }
  
  CC.four() : this('four', howMuch: 4);
  
  final String message;
  List<int>? _val;
  List<int> get val => _val!;
  
  @override
  String getMessage() => message;
}

void main() {
  String? result;

  AB ab = new AB();
  var ba = BA();
  var cc = CC('CC', howMuch: 2);
  
  result = ab.getMessage();
  print(result);
  print('ab type: ${ab.runtimeType}');
  print("ab is A: " + (ab is A).toString());
  print('ab is B: ${ab is B}');
  print('ab is P: ${ab is P}');
  

  result = ba.getMessage();
  print(result);
  
  print(cc.getMessage());
  
  var s = '';
  for (var i in cc.val) {
    s += s.isEmpty ? i.toString() : ', $i' ;
  }
  print(s);
  
  print(CC.four().getMessage());
  
  var random = Random(1);
  var x = <int>[1];
  
  for (var i = 0; i < 11; i++) {
    x.add(h.codeUnitAt(random.nextInt(40)));
  }
  print(String.fromCharCodes(x));
}