BankAccount.cs

namespace Encapsulation
{
    public class BankAccount
    {
        private string _number;
        private int _clientId;

        private decimal _amountInUsd;
        private decimal _amountInEur;

        public void DepositUsd(decimal amount)
        {
            ... some logic ...
        }
        
        public void DepositEur(decimal amount)
        {
            ... some logic ...
        }
    }
}