using System;

using Newtonsoft.Json.Schema;

using System.Collections;

using System.Collections.Generic;

//nuget Newtonsoft.Json.Schema v2.0.8

​

public class Program

{

    public static void Main()

    {

        List<Dog> dogs = new List<Dog>();

        dogs.Add(new Dog("Fido"));

        dogs.Add(new Retriever("Dave", "Golden"));

        dogs.Add(new Pitbull("John"));

        foreach(Dog dog in dogs)

        {

            Console.WriteLine(dog);

        }

​

    }

    static void PrintPopulation()

    {

        Console.WriteLine("Total Population is " + Person.Population);

    }

}

​

public class Dog

{

    public string Name;

    public Dog(string name)

    {

        Name = name;

    }

    public override string ToString()

    {

        return "The dog's name is " + Name; 

    }

}

​

public class Retriever : Dog

{

    public string RetrieverType;

    public Retriever(string name, string retrieverType)

        : base(name)

    {

        RetrieverType = retrieverType;

    }

    public override string ToString()

    {

        return "The retriever's name is " + Name + " and type is " + RetrieverType; 

    }

}

​

public class Pitbull : Dog

{

    public Pitbull(string name)

        : base(name)

    {

    }

}

​

class Person

{

    public static int Population;

    public string FirstName;

    public string LastName;

    public bool Alive;

    public int Age;

    public Person(string firstName, string lastName)

    {

        Population++;

        FirstName = firstName;

        LastName = lastName;

        Age = 0;

        Alive = true;

    }

    public void GiveBirthday()

    {

        Age++;

    }

    public void Kill()

    {

        Population--;

        Alive = false;

    }

    public override string ToString()

    {

        return FirstName + LastName + ", age " + Age + ". Alive: " + Alive;

    }

}

/*

Memory: ~ 390 kb

CPU:    0.766s

​

*/