using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Identify the Persons as per Enum Provided :");

        List<Person> existingPersons = new List<Person>

        {

            new Person { Id = 1, Name = "Person 1" },

            new Person { Id = 3, Name = "Person 33" },

            new Person { Id = 5, Name = "Person 5" },

            new Person { Id = 7, Name = "Person 7" },

            new Person { Id = 9, Name = "Person 9" }

        };

        List<Person> newPersons = new List<Person>

        {

            new Person { Id = 3, Name = "Person 3" },

            new Person { Id = 6, Name = "Person 6" },

            new Person { Id = 9, Name = "Person 99" },

            new Person { Id = 12, Name = "Person 12" },

            new Person { Id = 15, Name = "Person 15" }

        };

        var result = GetPersonUpdates(existingPersons,newPersons);

        foreach(var item in result)

        {

            Console.WriteLine(item.Person.Id +  " " + item.Person.Name+  " " + item.UpdateType);

        }

        Console.WriteLine("Completed !!");

    }

    static IEnumerable<PersonAdditionalDetails> GetPersonUpdates(IEnumerable<Person> existingPersons,IEnumerable<Person> newPersons)

    {

         var result = new List<PersonAdditionalDetails>();

​

    // Check for new persons

    foreach (var newPerson in newPersons)

    {

        bool exists = existingPersons.Any(p => p.Id == newPerson.Id);

​

        if (!exists)

        {

            result.Add(new PersonAdditionalDetails { Person = newPerson, UpdateType = UpdateType.Add });

        }

        else

        {

            var existingPerson = existingPersons.First(p => p.Id == newPerson.Id);

​

            if (existingPerson.Name != newPerson.Name)

            {

                result.Add(new PersonAdditionalDetails { Person = newPerson, UpdateType = UpdateType.Modify });

            }

        }

    }

​

    // Check for deleted persons

    foreach (var existingPerson in existingPersons)

    {

        bool exists = newPersons.Any(p => p.Id == existingPerson.Id);

​

        if (!exists)

        {

            result.Add(new PersonAdditionalDetails { Person = existingPerson, UpdateType = UpdateType.Delete });

        }

    }

​

    return result;

    }

}

​

public class Person

{

    public int Id { get; set; }

    public string Name { get; set; }

}

​

public enum UpdateType

{

    Add,    // if person is not available in existingPersons

    Modify, // if available in both but name is different

    Delete  // if not available in newPersons

}

​

public class PersonAdditionalDetails

{

    public Person Person { get; set; }

    public UpdateType UpdateType { get; set; }

}