<?php
class BankAccount
{
protected $balance = 0;
public function getBalance()
{
return $this->balance;
}
protected function setBalance($balance)
{
if ($balance >= 0) {
$this->balance = $balance;
} else {
throw new RuntimeException;
}
}
public function depositMoney($balance)
{
$this->setBalance($this->getBalance() + $balance);
return $this->getBalance();
}
public function withdrawMoney($balance)
{
$this->setBalance($this->getBalance() - $balance);
return $this->getBalance();
}
}