public partial class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }

    partial void OnNameChanged();

    public void ChangeName(string firstName, string lastName)
    {
        FirstName = firstName;
        LastName = lastName;
        OnNameChanged();
    }
}

public partial class Person
{
    partial void OnNameChanged()
    {
        Console.WriteLine($"Name changed to: {FirstName} {LastName}");
    }
}

class Program
{
    static void Main(string[] args)
    {
        Person person = new Person();
        person.ChangeName("John", "Doe");
        // Выведет: Name changed to: John Doe
    }
}

      class MathOperations
   {
       public int Multiply(int a, int b)
       {
           return a * b;
       }

       public int Multiply(int a, int b, int c)
       {
           return a * b * c;
       }
   }   

      class Animal
   {
       public virtual void MakeSound()
       {
           Console.WriteLine("Some sound");
       }
   }

   class Dog : Animal
   {
       public override void MakeSound()
       {
           Console.WriteLine("Woof");
       }
   }   

public abstract class Животное
{
    public abstract void Голос(); // Абстрактный метод, определение голоса животного
}

public class Собака : Животное
{
    public override void Голос()
    {
        Console.WriteLine("Гав");
    }
}

public class Кошка : Животное
{
    public override void Голос()
    {
        Console.WriteLine("Мяу");
    }
}

class Program
{
    static void Main(string[] args)
    {
        Животное мояСобака = new Собака();
        мояСобака.Голос(); // Вывод: Гав

        Животное мояКошка = new Кошка();
        мояКошка.Голос(); // Вывод: Мяу
    }
}

using (var context = new BloggingContext())
{
    var blog = new Blog { Url = "https://blogs.msdn.com/adonet" };
    context.Blogs.Add(blog);
    context.SaveChanges();

    var blogs = context.Blogs
                       .Where(b => b.Url.Contains("msdn"))
                       .ToList();
    foreach (var b in blogs)
    {
        Console.WriteLine(b.Url);
    }
}

public struct Point
{
    public int X;
    public int Y;

    public Point(int x, int y)
    {
        X = x;
        Y = y;
    }
}

public class Circle
{
    public Point Center;
    public double Radius;

    public Circle(int x, int y, double radius)
    {
        Center = new Point(x, y);
        Radius = radius;
    }
}

public interface IService
{
    void Execute();
}

public class ServiceLocator
{
    private IDictionary<object, IService> services;

    public ServiceLocator()
    {
        services = new Dictionary<object, IService>();
    }

    public void RegisterService<T>(IService service)
    {
        services.Add(typeof(T), service);
    }

    public IService GetService<T>()
    {
        return services[typeof(T)];
    }
}

public class ConcreteService : IService
{
    public void Execute()
    {
        Console.WriteLine("Service Executed");
    }
}

class Program
{
    static void Main()
    {
        ServiceLocator locator = new ServiceLocator();
        locator.RegisterService<IService>(new ConcreteService());

        IService service = locator.GetService<IService>();
        service.Execute();  // Output: Service Executed
    }
}