CurrentAccounts.cs

using System;
using Wrox.ProCSharp;
using Wrox.ProCSharp.VenusBank;
using Wrox.ProCSharp.JupiterBank;

namespace Wrox.ProCSharp
{
   class MainEntryPoint
   {
      static void Main()
      {
        IBankAccount venusAccount = new SaverAccount();
                ITransferBankAccount jupiterAccount = new CurrentAccount();
                venusAccount.PayIn(200);
                jupiterAccount.PayIn(500);
                jupiterAccount.TransferTo(venusAccount, 100);
                Console.WriteLine(venusAccount.ToString());
                Console.WriteLine(jupiterAccount.ToString());
      }
   }
}


namespace Wrox.ProCSharp
{
   public interface IBankAccount
   {
      void PayIn(decimal amount);
      bool Withdraw(decimal amount);
      decimal Balance
      {
         get;
      }
   }
    
    
     public interface ITransferBankAccount : IBankAccount
   {
      bool TransferTo(IBankAccount destination, decimal amount);
   }
}

namespace Wrox.ProCSharp.VenusBank
{
   public class SaverAccount : IBankAccount
   {
      private decimal balance;
      public void PayIn(decimal amount)
      {
         balance += amount;
      }
      public bool Withdraw(decimal amount)
      {
         if (balance >= amount)
         {
            balance -= amount;
            return true;
         }
         Console.WriteLine("Withdrawal attempt failed.");
         return false;
      }
      public decimal Balance
      {
         get
         {
            return balance;
         }
      }
      public override string ToString()
      {
         return String.Format("Venus Bank Saver: Balance = {0,6:C}", balance);
      }
   }
}



namespace Wrox.ProCSharp.JupiterBank
{
   public class CurrentAccount : ITransferBankAccount
{
   private decimal balance;
   public void PayIn(decimal amount)
   {
      balance += amount;
   }
   public bool Withdraw(decimal amount)
   {
      if (balance >= amount)
      {
         balance -= amount;
         return true;
      }
      Console.WriteLine("Withdrawal attempt failed.");
      return false;
   }
   public decimal Balance
   {
      get
      {
         return balance;
      }
   }
   public bool TransferTo(IBankAccount destination, decimal amount)
   {
      bool result;
      if ((result = Withdraw(amount)) == true)
         destination.PayIn(amount);
      return result;
   }
   public override string ToString()
   {
      return String.Format("Jupiter Bank Current Account: Balance = {0,6:C}",
                                                                      balance);
   }   
 
}


}