Encapsulation example in c#

1. BankAccountExternal.cs

using System;
public class BankAccountExternal
{
    public decimal GetAmount()
    {
        return 2000.00m;
    }
}

2. BankAccountPrivate.cs

using System;
class BankAccountPrivate
{
    private string m_name;
    public string CustomerName
    {
        get { return m_name; }
        set { m_name = value; }
    }
}

3. BankAccountProtected.cs

using System;
class BankAccountProtected
{
    public void CloseAccount()
    {
        ApplyPenalties();
        CalculateFinalInterest();
        DeleteAccountFromDB();
    }
    protected virtual void ApplyPenalties()
    {
        // deduct from account
    }
    protected virtual void CalculateFinalInterest()
    {
        // add to account
    }
    protected virtual void DeleteAccountFromDB()
    {
        // send notification to data entry personnel
    }
}

4. BankAccountPublic.cs

using System;
class BankAccountPublic
{
    public decimal GetAmount()
    {
        return 1000.00m;
    }
}

5. CheckingAccount.cs

using System;
class CheckingAccount : BankAccountProtected
{
    protected override void ApplyPenalties()
    {
        Console.WriteLine("Checking Account Applying Penalties");
    }
    protected override void CalculateFinalInterest()
    {
        Console.WriteLine("Checking Account Calculating Final Interest");
    }
    protected override void DeleteAccountFromDB()
    {
        base.DeleteAccountFromDB();
        Console.WriteLine("Checking Account Deleting Account from DB");
    }
}

6. InternalInterestCalculator.cs

using System;
internal class InternalInterestCalculator
{
    // members go here
}

7. SavingsAccount.cs

using System;
class SavingsAccount : BankAccountProtected
{
    protected override void ApplyPenalties()
    {
        Console.WriteLine("Savings Account Applying Penalties");
    }
    protected override void CalculateFinalInterest()
    {
        Console.WriteLine("Savings Account Calculating Final Interest");
    }
    protected override void DeleteAccountFromDB()
    {
        base.DeleteAccountFromDB();
        Console.WriteLine("Savings Account Deleting Account from DB");
    }
}

8. Program.cs

using System;
class Program
{
    static void Main()
    {
        BankAccountPublic bankAcctPub = new BankAccountPublic();
        // call a public method
        decimal amount = bankAcctPub.GetAmount();
        Console.WriteLine("Bank Account Amount: " + amount);
        BankAccountProtected[] bankAccts = new BankAccountProtected[2];
        bankAccts[0] = new SavingsAccount();
        bankAccts[1] = new CheckingAccount();
        foreach (BankAccountProtected acct in bankAccts)
        {
            // call public method, which invokes protected virtual methods
            acct.CloseAccount();
        }
        BankAccountExternal BankAcctExt = new BankAccountExternal();
        // call a public method
        amount = BankAcctExt.GetAmount();
        Console.WriteLine("External Bank Account Amount: " + amount);
    }
}