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Python

Posted by Jami Schwarzwalder
Jami Schwarzwalder
17,961 Points

What am I doing wrong?

I can't quite figure out what I did wrong in my code? It doesn't seem to handle fees properly but my first test works...

class BankAccount:
    """ Class definition modeling the behavior of a simple bank account """

    def __init__(self, initial_balance):
        """Creates an account with the given balance."""
        self.balance = initial_balance
        self.fee = 0
    def deposit(self, amount):
        """Deposits the amount into the account."""
        self.balance += amount
    def withdraw(self, amount):
        """
        Withdraws the amount from the account.  Each withdrawal resulting in a
        negative balance also deducts a penalty fee of 5 dollars from the balance.
        """
        self.balance -= amount
        print self.balance
        if (self.balance < 0):
            self.balance -=  5
            #print self.balance
            self.fee +=1
            #print self.fee

        else:
            self.balance -= amount
    def get_balance(self):
        """Returns the current balance in the account."""
        return self.balance
    def get_fees(self):
        """Returns the total fees ever deducted from the account."""
        return self.fee * 5 
my_account = BankAccount(10)
my_account.withdraw(15)
my_account.deposit(20)
my_account.withdraw(15)
my_account.deposit(20)
my_account.withdraw(15)
my_account.deposit(20)
my_account.withdraw(15)
my_account.deposit(20)
print my_account.get_balance(), my_account.get_fees()
Trevor Currie
Trevor Currie
9,289 Points

What is the functionality you desire? Right now it looks like you have functioning code.... Do you have errors?

(Please elaborate)

2 Answers

William Li
William Li
Courses Plus Student 26,868 Points

Hi, Jami Schwarzwalder At first glance, I can see there's problem with the withdraw method

    def withdraw(self, amount):
        """
        Withdraws the amount from the account.  Each withdrawal resulting in a
        negative balance also deducts a penalty fee of 5 dollars from the balance.
        """
        self.balance -= amount
        print self.balance
        if (self.balance < 0):
            self.balance -=  5
            #print self.balance
            self.fee +=1
            #print self.fee

        else:
            self.balance -= amount

First there's this line self.balance -= amount that subtracts the amount from self.balance.

then enter the if...else conditional, if the leftover balance is not negative, it will call in this statment self.balance -= amount at the else clause to subtract the amount from balance AGAIN.

So this is a semantic problem here because the method can double withdraw the amount so long as the balance is above 0.

Jami Schwarzwalder
Jami Schwarzwalder
17,961 Points
Jami Schwarzwalder
Jami Schwarzwalder
17,961 Points

The code does work there,

but when i tried to do other amounts it doesn't calculate correctly

I don't know why it only works for those amounts.