Разработать интерфейс класса, содержащий операции получения процентной ставки

using System;
 
public class Account
{
    private string owner;
    private double intrate;
    private decimal balance; 
    private int id;
    private static int nextid = 555; 
 
    public Account(string owner, double intrate, decimal balance)
    {
        this.owner = owner;
        this.intrate = intrate;
        this.balance = balance;
        this.id = nextid++;
    } 
     
 
    public string Getowner ()
    {
        return owner;
    }
    public double Getintrate ()
    {
        return intrate;
    }
    public decimal GetBalance()
    {
        return balance;
    }
    public int GetId()
    {
        return id;
    }
}
 
public class StaticConstructor
{
    
    public static void Main(string[] args)
                                   {
        Account acc1, acc2, acc3;
    
        acc1 = new Account("Anton", 12, 32400); 
 
        acc2 = new Account("Alexandr", 12, 15000); 
        acc3 = new Account("Dmitriy", 10, 5264); 
        WriteAccount(acc1); 
        WriteAccount(acc2); 
        WriteAccount(acc3);
      }
private static void WriteAccount(Account acc)
      {
        Console.WriteLine("Owner: {0}, intrate: {1}, balance of id: {2} is {3} ",
                          acc.Getowner(),
                          acc.Getintrate(),
                          acc.GetId(), acc.GetBalance());
                        
      }
 
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
public interface IAccount
{
    double Getintrate();
    decimal GetBalance();
    int GetId();
}
 
public class Account : IAccount
{
    private string owner;
    private double intrate;
    private decimal balance;
    private int id;
    private static int nextid = 555;
    private const int Discont = 2;
    public bool Before
    {
        set
        {
            if (value) intrate -= Discont;
        }
    }
 
    public Account(string owner, double intrate, decimal balance)
    {
        this.owner = owner;
        this.intrate = intrate;
        this.balance = balance;
        this.id = nextid++;
    }
 
    public string Getowner()
    {
        return owner;
    }
    public double Getintrate()
    {
        return intrate;
    }
    public decimal GetBalance()
    {
        return balance;
    }
    public int GetId()
    {
        return id;
    }
    public override string ToString()
    {
        return String.Format("Owner: {0}, Interate: {1}, Balance: {2}, ID: {3}", owner, intrate, balance, id);
    }
 
}
 
public class Bank
{
    List<Account> BankList = new List<Account>();
    public void AddAccount(params Account[] acc)
    {
        BankList.AddRange(acc);
        for (int i = 0; i < acc.Length; i++)
            Console.WriteLine("Добавлен: {0}", acc[i].ToString());
    }
    public void DeleteAccount(bool before, Account acc)
    {
        acc.Before = before;
        BankList.Remove(acc);
        Console.WriteLine("Удален: {0}", acc.ToString());
    }
    public override string ToString()
    {
        string str = "\nСчета в банке:\n";
        for (int i=0; i<BankList.Count; i++)
            str+=String.Format(BankList[i].ToString()+"\n");
        return str;
    }
}
 
public class StaticConstructor
{
 
    public static void Main(string[] args)
    {
        Account acc1, acc2, acc3;
        Bank Bank1 = new Bank();
 
        acc1 = new Account("Anton", 12, 32400);
        acc2 = new Account("Alexandr", 12, 15000);
        acc3 = new Account("Dmitriy", 10, 5264);
 
        Bank1.AddAccount(acc1, acc2, acc3);
 
        Console.WriteLine(Bank1.ToString());
 
        Bank1.DeleteAccount(true, acc1);
        Bank1.DeleteAccount(false, acc2);
        Bank1.DeleteAccount(true, acc3);
 
        Console.WriteLine(Bank1.ToString());
        Console.ReadLine();
    }
}