DepositMoney.cs

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

        private decimal _amountInUsd;
        private decimal _amountInEur;

        public void DepositUsd(decimal amount)
        {
            if (amount <= 0)
            {
                throw new ArgumentException("Values less or equal zero are not allowed!");
            }
        
            _amountInUsd += amount;
        }
        
        public void DepositEur(decimal amount)
        {
            if (amount <= 0)
            {
                throw new ArgumentException("Values less or equal zero are not allowed!");
            }
        
            _amountInEur += amount;
        }
    }
}