Compile and Execute C# Sharp Online

using System.IO;
using System;

class SubsystemA

    {

        public void ValidateUser(string userName, string password)

        {

            Console.WriteLine("Validate user credentials...");

        }

    }
    class SubsystemB

    {

        public void ValidateCreditCard(string cardNumber)

        {

            Console.WriteLine("Validate credit card...");

        }

        public void PayAmount(string cardNumber, double amount)

        {

            Console.WriteLine("Pay amount...");

        }

    }
    
    public class Facade

    {

        SubsystemA firstSubsystem = new SubsystemA();

        SubsystemB secondSubsystem = new SubsystemB();

        public void Operation1(string userName, string password)

        {

            firstSubsystem.ValidateUser(userName, password);

        }

        public void Operation2(string cardNumber, double amount)

        {

            secondSubsystem.ValidateCreditCard("1234567890");

            secondSubsystem.PayAmount(cardNumber, amount);

        }
    }

        class Program

    {

      static void Main(string[] args)

        {

            Facade facade = new Facade();

            facade.Operation1("Joydip", "Joydip123");

            facade.Operation2("1234567890", 100.00);

            Console.Read();

        }

     }