using System;

​

// Abstract class BankAccount

abstract class BankAccount

{

    protected string accountHolderName;

    protected string accountNumber;

    protected double balance;

​

    public BankAccount(string accountHolderName, string accountNumber, double balance)

    {

        this.accountHolderName = accountHolderName;

        this.accountNumber = accountNumber;

        this.balance = balance;

    }

​

    // Abstract methods to be implemented by derived classes

    public abstract void Withdraw(double amount);

    public abstract void Deposit(double amount);

    public abstract void DisplayAccountDetails();

}

​

// Derived class Current from BankAccount

class Current : BankAccount

{

    public Current(string accountHolderName, string accountNumber, double balance) : base(accountHolderName, accountNumber, balance)

    {

    }

​

    public override void Withdraw(double amount)

    {

        if (amount > balance)

        {

            Console.WriteLine("Insufficient balance.");

        }

        else

        {

            balance -= amount;

            Console.WriteLine("Withdrawal of {0} successful.",amount);

        }

    }

​

    public override void Deposit(double amount)

    {

        balance += amount;

        Console.WriteLine("Deposit of {0} successful.",amount);

    }

​

    public override void DisplayAccountDetails()

    {

        Console.WriteLine("Account Type: Current");

        Console.WriteLine("Account Holder Name: {0}",accountHolderName);

        Console.WriteLine("Account Number: {0}",accountNumber);

        Console.WriteLine("Balance: {0}",balance);

    }

}

​

// Derived class Savings from BankAccount

class Savings : BankAccount

{

    private bool hasChequeBook;

​

    public Savings(string accountHolderName, string accountNumber, double balance, bool hasChequeBook) : base(accountHolderName, accountNumber, balance)

    {

        this.hasChequeBook = hasChequeBook;

    }

​

    public override void Withdraw(double amount)

    {

        if (amount > balance)

        {

            Console.WriteLine("Insufficient balance.");

        }

        else

        {

            balance -= amount;

            Console.WriteLine("Withdrawal of {0} successful.",amount);

        }

    }

​

    public override void Deposit(double amount)

    {

        balance += amount;

        Console.WriteLine("Deposit of {0} successful.",amount);

    }

​

    public override void DisplayAccountDetails()

    {

        Console.WriteLine("Account Type: Savings");

        Console.WriteLine("Account Holder Name: {0}",accountHolderName);

        Console.WriteLine("Account Number: {0}",accountNumber);

        Console.WriteLine("Balance: {0}",balance);

        Console.WriteLine("Cheque Book Facility: {0}",hasChequeBook ? "Available" : "Not Available");

    }

}

​

// Derived class Fixed from BankAccount

abstract class Fixed : BankAccount

{

    protected double interestRate;

​

    public Fixed(string accountHolderName, string accountNumber, double balance, double interestRate) : base(accountHolderName, accountNumber, balance)

    {

        this.interestRate = interestRate;

    }

​

    public double CalculateInterest(int years)

    {

        return balance * interestRate * years / 100;

    }

}

​

// Derived class ShortTerm from Fixed

class ShortTerm : Fixed

{

    public ShortTerm(string accountHolderName, string accountNumber, double balance) : base(accountHolderName, accountNumber, balance, 8)

    {

    }

​

    public override void Withdraw(double amount)

    {

        Console.WriteLine("Withdrawal facility not available for Short Term Fixed Account.");

    }

​

    public override void Deposit(double amount)

    {

        Console.WriteLine("Deposit facility not available for Short Term Fixed Account.");

    }

​

    public override void DisplayAccountDetails()

    {

        Console.WriteLine("Account Type: Short Term Fixed");

        Console.WriteLine("Account Holder Name: {0}",accountHolderName);

        Console.WriteLine("Account Number: {0}",accountNumber);

        Console.WriteLine("Balance: {0}",balance);

    }

}

​

// Derived class LongTerm from Fixed

class LongTerm : Fixed

{

    public LongTerm(string accountHolderName, string accountNumber, double balance) : base(accountHolderName, accountNumber, balance, 10)

    {

    }

​

    public override void Withdraw(double amount)

    {

        Console.WriteLine("Withdrawal facility not available for Long Term Fixed Account.");

    }

​

    public override void Deposit(double amount)

    {

        Console.WriteLine("Deposit facility not available for Long Term Fixed Account.");

    }

​

    public override void DisplayAccountDetails()

    {

        Console.WriteLine("Account Type: Long Term Fixed");

        Console.WriteLine("Account Holder Name: {0}",accountHolderName);

        Console.WriteLine("Account Number: {0}",accountNumber);

        Console.WriteLine("Balance: {0}",balance);

    }

}

​

public class Program

{

   public static void Main(string[] args)

    {

        // Driver program to test the classes

​

        // Create Current Account

        BankAccount currentAccount = new Current("John ", "C001", 5000);

        currentAccount.DisplayAccountDetails();

        currentAccount.Deposit(2000);

        currentAccount.Withdraw(1000);

        currentAccount.DisplayAccountDetails();

​

        // Create Savings Account

        BankAccount savingsAccount = new Savings("Alice ", "S001", 10000, true);

        savingsAccount.DisplayAccountDetails();

        savingsAccount.Deposit(5000);

        savingsAccount.Withdraw(3000);

        savingsAccount.DisplayAccountDetails();

​

        // Create Short Term Fixed Account

        BankAccount shortTermFixedAccount = new ShortTerm("Bob ", "STF001", 20000);

        shortTermFixedAccount.DisplayAccountDetails();

        Console.WriteLine("Interest Earned (1 year): {0}",((ShortTerm)shortTermFixedAccount).CalculateInterest(1));

        Console.WriteLine("Interest Earned (2 years): {0}",((ShortTerm)shortTermFixedAccount).CalculateInterest(2));

​

        // Create Long Term Fixed Account

        BankAccount longTermFixedAccount = new LongTerm("Eva ", "LTF001", 30000);

        longTermFixedAccount.DisplayAccountDetails();

        Console.WriteLine("Interest Earned (3 years): {0}",((LongTerm)longTermFixedAccount).CalculateInterest(3));

        Console.WriteLine("Interest Earned (5 years): {0}",((LongTerm)longTermFixedAccount).CalculateInterest(5));

    }

}

​