void main() {
class PersonV1 {
  String fname;
  String lname;
  void display() {
    print("Fname: $fname, Lname: $lname");
  }

void main() {
  var obj1 = PersonV1();
  obj1.display();
class PersonV1 {
  String fname;
  String lname;
void display() {
    print("Fname: $fname, Lname: $lname");
  }

Fname: null, Lname: null

void main() {
  // class
  var obj1 = PersonV1();
  obj1.fname = "Expert";
  obj1.lname = "Programming";
  obj1.display();
var obj2 = PersonV2();
  obj2.display();]
class PersonV1 {
String fname;
String lname;
void display() {
print("Fname: $fname, Lname: $lname");
}

void main() {
  // class
  var obj1 = PersonV1();
//  obj1.fname = "Expert";
//  obj1.lname = "Programming";
  obj1.display();
  var obj2 = PersonV2();
  obj2.display();
class PersonV1 {
  String fname;
  String lname;
void display() {
    print("Fname: $fname, Lname: $lname");
  }
}
class PersonV2 {
  String fname;
  String lname;
  PersonV2() {
    this.fname = "none";
    this.lname = "none";
  }

Fname: null, Lname: null
Fname: none, Lname: none

void main() {
  // class
  var obj1 = PersonV1();
//  obj1.fname = "Expert";
//  obj1.lname = "Programming";
  obj1.display();
  var obj2 = PersonV2();
  obj2.display();
  //constructor named
  var obj3 = PersonV2("CAT", "MEOW");
  obj3.display()

PersonV2(String fname, String lname) {
    this.fname = fname;
    this.lname = lname;
  }
  void display() {
    print("Fname: $fname, Lname: $lname");
 }

PersonV2.tutor_name(String fname, String lname) {
    this.fname = fname;
    this.lname = lname;
  }
var obj3 = PersonV2.tutor_name("CAT", "MEOW");
  obj3.display();

class PersonV3 {
  String fname;
  String lname;
  PersonV3() {
   this.fname = "none";
    this.lname = "none";
  }
    PersonV3.tutor_name(String fname, String lname) {
    this.fname = fname;
    this.lname = lname;
  }
    void set nameMele(String fname) {
    this.fname = "Mr. ${fname}";
  }
   void set namefeMele(String lname) {
   this.fname = "Mrs. ${lname}";
  }
   String get vipMember {
   return "[VIP] $fname $lname";
  }
   void display() {
   print("Fname: $fname, Lname: $lname");
  }
}

  void set nameMele(String fname) {
    this.fname = "Mr. ${fname}";
  }
  void set namefeMele(String lname) {
    this.fname = "Mrs. ${lname}";
  }

  String get vipMember {
    return "[VIP] $fname $lname";
  }
  void display() {
    print("Fname: $fname, Lname: $lname");
  }
}

class PersonV4 {
  String fname;
  String lname;
  PersonV4() {
    this.fname = "none";
    this.lname = "none";
  }
   PersonV4.tutor_name(String fname, String lname) {
   this.fname = fname;
   this.lname = lname;
  }
   void set nameMele(String fname) {
   this.fname = "Mr. ${fname}";
  }
   void set namefeMele(String lname) {
   this.fname = "Mrs. ${lname}";
  }
  String get vipMember {
    return "[VIP] $fname $lname";
  }
    void display() {
    print("fname: $fname, Lname: $lname");
  }

void main() {
  // class
  var obj1 = PersonV1();
//  obj1.fname = "Expert";
//  obj1.lname = "Programming";
  obj1.display();
  var obj2 = PersonV2();
  obj2.display();
  //constructor named
  var obj3 = PersonV2.tutor_name("CAT", "MEOW");
  obj3.display();
    //getter , setter
  var obj4 = PersonV3.tutor_name("CAT", "MEOW");
  obj4.nameMele = "Expert";
  obj4.display();
  print(obj4.vipMember);

Fname: null, Lname: null
Fname: none, Lname: none
Fname:CAT, Lname: MEOW
Fname: Mr . Expert, Lname: MEOW
[VIP] Mr . Expert MEOW
none

Fname: null, Lname: null
Fname: none, Lname: none
Fname:CAT, Lname: MEOW
Fname: Mr . Expert, Lname: MEOW
[VIP] Mr . Expert MEOW

  // callable
  var obj5 = PersonV4();
  obj5.namefeMele = "CAT";
  print(obj5());
}
  String call() {
    return fname;
  }
}

Fname: null, Lname: null
Fname: none, Lname: none
Fname:CAT, Lname: MEOW
Fname: Mr . Expert, Lname: MEOW
[VIP] Mr . Expert MEOW
none

  // callable
  var obj5 = PersonV4();
  obj5.namefeMele = "CAT";
  print(obj5());
}

Fname: null, Lname: null
Fname: none, Lname: none
Fname:CAT, Lname: MEOW
Fname: Mr . Expert, Lname: MEOW
[VIP] Mr . Expert MEOW
Mrs. CAT