import 'dart:io';
  
void main() {
  
  Employee eman= Employee(18, "Eman", "helal@mail.com", "Google");
  eman.displayInfo();
  
  Client ahmed= Client(45, "Ahmed", "Ahmed@gmail.com");
  ahmed.set_Compain("Google");
  ahmed.set_Compain("Amazon");
  ahmed.set_Compain("Youtube");
  ahmed.displayCompains();
}
class Person{
  int? age; 
  String? name;
  String? mail;
  Person(this.age, this.name,this.mail);
  
  void displayInfo(){ 
    print("${name} has ${age} years old and his mail is ${mail}");}
  
}

class Employee extends Person{
  String? worksOnCompain;
  Employee( int age,String name,String mail, String  this.worksOnCompain):super(age,name,mail);
  @override
    void displayInfo(){ 
    print("${name} has ${age} years old and his mail is ${mail} and works on ${worksOnCompain}") ;}
  
}

class Client extends Person{
  List<String> compain = [];
  Client( int age,String name,String mail):super(age,name,mail);
  void set_Compain(String com){
    compain.add(com);
  }
  
  
    void displayCompains(){ 
      print("${name} is in");
    for(int i=0; i<compain.length; i++){
    print("${compain[i]}") ;}
    }
  
}

class Compain{
  String? compainName;
  String? startDate;
  String? endDate;
  String? platform;
  //String type= [""];
  Compain( {this.compainName,this.startDate,this.endDate,this.platform}){
  }
  
  void displayCompainInfo(){ 
    print("The ${compainName} on platform ${platform} starts at ${startDate} and ends at ${endDate}");}
  
}