using System;

using Microsoft.Extensions.DependencyInjection;

public class Program

{

    public static void Main()

    {

        var services = new ServiceCollection();

        services.AddTransient<IService, MyService>();

        //services.AddTransient<IOtherService, MyOtherService>();

        services.AddTransient<IServiceManager, ServiceManager>();

        var provider = services.BuildServiceProvider();

        IServiceManager serviceManager = provider.GetRequiredService<IServiceManager>();

        serviceManager.Print();

    }

    public interface IServiceManager

    {

        void Print();

    }

    public class ServiceManager : IServiceManager

    {

        private readonly IService service;

        private readonly IOtherService otherService;

        public ServiceManager(IService service, IOtherService otherService)

        {

            this.service = service;

            this.otherService = otherService;

            Console.WriteLine("ServiceManager(IService service, IOtherService otherService) called");

        }

        public ServiceManager(IService service)

        {

            this.service = service;

            Console.WriteLine("ServiceManager(IService service) called");

        }

        public void Print()

        {

            Console.WriteLine();

            Console.WriteLine("Service injected: " + !(service is null));

            Console.WriteLine("Other service injected: " + !(otherService is null));

        }

    }

    public interface IService

    {

    }

    public class MyService : IService

    {

    }

    public interface IOtherService

    {

    }

    public class MyOtherService : IOtherService

    {

    }

}