2. félév 2. óra (otthon)

namespace Inheritance
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //Person person01 = new Person("Primoz", "Roglic");
            //Console.WriteLine(person01); // = person01.ToString()

            //Employee employee01 = new Employee("Tadej", "Pogacar", 5000);
            //Console.WriteLine(employee01.Name);
            //Console.WriteLine(employee01);

            //Console.WriteLine(employee01.GetEmailAddress());

            //Person person02 = new Employee("Wout", "Van art", 4000);
            //Console.WriteLine(person02.FirstName);
            //Console.WriteLine(person02.LastName);

            //if (person02 is Employee)
            //{
            //    //Employee employee02 = person02 as Employee;

            //    (person02 as Employee).GetEmailAddress();
            //}

            //Employee employee03 = person01 as Employee; // null
            //if (employee03 != null)
            //{
            //    Console.WriteLine(employee03.GetEmailAddress());
            //}

            //Console.WriteLine((person02 as Employee)?.GetEmailAddress() ?? "Not an employee");
            //Console.WriteLine((employee03 as Employee)?.GetEmailAddress() ?? "Not an employee");


            //CEO ceo = new CEO("Gerant", "Thomas");
            //Console.WriteLine(ceo.GetEmailAddress());

            //Employee employee04 = new CEO("Attila", "Valter");
            //Console.WriteLine(employee04.GetEmailAddress()); // késői kötés => ha nincsen override a CEO metódusnál, akkor korai kötés

            //object obj = new Person("Tom", "Pidcock");




            //Person person01 = new Person("Primoz", "Roglic");
            //Person person02 = new Person("Primoz", "Roglic");

            //if (person01 == person02)
            //{
            //    Console.WriteLine("Same");
            //}
            //else { Console.WriteLine("Different"); }

            //if (person01.Equals(person02))
            //{
            //    Console.WriteLine("SAME");
            //}
            //else { Console.WriteLine("Different"); }




            Person[] persons = { new Employee("Primoz", "Roglic", 3000), new CEO("Attila", "Valter"), new Student("Hanna", "Hallgato")};
            foreach (Person currentPerson in persons)
            {
                Console.WriteLine(currentPerson.GetEmailAddress());
            }
        }
    }
}

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Osztályok
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Inheritance
{
    abstract class Person : object
    {
        protected string firstName;
        protected string lastName;

        public string FirstName { get { return firstName; } set { firstName = value; } }
        public string LastName { get { return lastName; } set { lastName = value; } }
        public string Name => $"{firstName} {lastName}";

        public Person(string firstName, string lastName)
        {
            this.firstName = firstName;
            this.lastName = lastName;
        }

        public abstract string GetEmailAddress(); // virtual

        public override string ToString()
        {
            return Name;
        }

        public override bool Equals(object? obj)
        {
            if (!(obj is Person)) return false;

            Person other = obj as Person;

            return firstName == other.firstName && lastName == other.lastName;
        }
    }
}

---------------------------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Inheritance
{
    internal class Employee : Person
    {
        int salary;

        public int Salary { get => salary; set => salary=value;}

        public override string GetEmailAddress() => $"{firstName.ToLowerInvariant()}.{lastName.ToLowerInvariant()}@company.com";

        public Employee(string firstName, string lastName, int salary) : base(firstName, lastName)
        {
            this.salary = salary;
        }

        public override string ToString()
        {
            return base.ToString() + " (" + GetEmailAddress() + ")";
        }
    }
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Inheritance
{
    sealed class CEO : Employee
    {
        public CEO(string firstName, string lastName) : base(firstName, lastName, 10000)
        {
        }

        public override string GetEmailAddress() => "ceo@company.com";
    }
}

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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Inheritance
{
    internal class Student : Person
    {
        public Student(string firstName, string lastName) : base(firstName, lastName)
        {
        }

        public override string GetEmailAddress()
        {
            return $"{firstName}.{lastName}@university.com";
        }
    }
}