Class bank_account {
public:
  unsigned int deposit(unsigned int amount);
  int withdraw(unsigned int amount);
  unsigned int balance();

private:
  unsigned int current_balance;
}

void bank_account::bank_account()
{
  current_balance = 0;
}

void bank_account::~bank_account()
{
  if(current_balance != 0) {
    cout << "closing account with balance = $"
	 << current_balance << "\n";
  }
}

unsigned int bank_account::deposit(unsigned int amount)
{
  current_balance += amount;
  return(current_balance);
}

int bank_account::withdraw(unsigned int amount)
{
  if(amount > current_balance) {
    return(-1);
  }

  current_balance -= amount;
  return(current_balance);
}

unsigned int balance()
{
  return(current_balance);
}