Soultion

using System;
usingSystem.Collections.Generic;
usingSystem.Linq;
usingSystem.Text;

namespace bank_account
{
class BankAccount
{
protected intaccountno;
protected string customer;
protected double balance;
protected DateTimeopendate;

public int Accountno
{ get { return accountno; } }

public string Customer
{ get { return customer; } }

public double Balance
{ get { return balance; } }

public DateTimeOpendate
{ get { returnopendate; } }

public BankAccount(int a, string c, double b)
{
 accountno = a;
 customer = c;
 balance = b;
 opendate = DateTime.Now;
}

public virtual void Display()
{
 Console.WriteLine("Account No.: {0} \nCustomer Name: {1} \nBalance: {2} \nOpen Date: {3}", accountno, customer, balance,          opendate);
 }

public void Deposite(double amount)
{
 balance += amount;
 Console.WriteLine("Balance after deposite {0} in it: {1}",amount,balance);
}

public virtual void withdraw(double amount)
{
  if (amount > balance)
  Console.WriteLine("amount is greater than balance, so Operation is Failed");
  else
{
   balance -= amount;
   Console.WriteLine("Balance after withdraw {0} from it: {1}", amount, balance);
}

}
}

class SpecialAccount : BankAccount
{
public double overlimit;

  public SpecialAccount(int a, string c, double b, double o)
   : base(a, c, b)
{
   overlimit = o;
}

public override void Display()
{
  base.Display();
  Console.WriteLine("Overlimit: {0}",overlimit);
}

public override void withdraw(double amount)
{
    if (amount > (balance + overlimit))
   Console.WriteLine("amount is greater than balance, so Operation is Failed");
else
{
  balance -= amount;
  Console.WriteLine("Balance after withdraw {0} from it: {1}", amount, balance);
  }
 }
}

classProgram
{
static void Main(string[] args)
   {
SpecialAccount s = newSpecialAccount(123, "bate5a", 3000, 1000);
s.Display();
s.Deposite(1000);
s.withdraw(4500);
     }
  }
}