class Account
{
Money balance;

Account(Money initialBalance)
  {
  balance = initialBalance;
  }

void deposit(Money amount)
  {
  balance = balance.add(amount);
  }

boolean withdraw(Money amount)
  {
  if( balance.lessThan(amount) )
    return false;
  balance = balance.subtract(amount);
  return true;
  }

void showBalance(PrintStream out)
  {
  out.println("Balance: " + balance);
  }

Only allow withdrawal if sufficient funds; return boolean to indicate success or failure.