선택적 매개변수

// 선택적 매개변수
class Person {
  String? name;
  int money;

  // 값이 들어오지 않을 때 기본 값 정의 가능
  Person({this.name, this.money = 0});
}

class Board{
  int id;
  String nickname;
  String? content;
  int? money;

  Board(this.id , {this.nickname = "aaa",this.content = "hi",this.money});
}


void main(){
  Person p1 = Person(name:"hgd");
  Person p2 = Person(name: "임꺽정", money: 1000);

  Board board = Board(1, content: "bye");
  print(p1.name);
  print(p1.money);
  
  print("${p2.name} and ${p2.money}");
  
  print("board: ${board.id}");
  print("board: ${board.nickname}");
  print("board: ${board.content}");
  print("board: ${board.money}");
}