Higher Order Functions

CS61A

def make_withdraw(balance, password):
    """Return a password-protected withdraw function.

    >>> w = make_withdraw(100, 'hax0r')
    >>> w(25, 'hax0r')
    75
    >>> error = w(90, 'hax0r')
    >>> error
    'Insufficient funds'
    >>> error = w(25, 'hwat')
    >>> error
    'Incorrect password'
    >>> new_bal = w(25, 'hax0r')
    >>> new_bal
    50
    >>> w(75, 'a')
    'Incorrect password'
    >>> w(10, 'hax0r')
    40
    >>> w(20, 'n00b')
    'Incorrect password'
    >>> w(10, 'hax0r')
    "Frozen account. Attempts: ['hwat', 'a', 'n00b']"
    >>> w(10, 'l33t')
    "Frozen account. Attempts: ['hwat', 'a', 'n00b']"
    >>> type(w(10, 'l33t')) == str
    True
    """
    "*** YOUR CODE HERE ***"
    times = 0
    attempts = []
    def bank(amount, pwd):
        nonlocal balance
        nonlocal times
        nonlocal attempts
        if times == 3:
            return "Frozen account. Attempts: " + str(attempts)
        elif pwd != password:
            times += 1
            attempts.append(pwd)
            return 'Incorrect password'
        elif balance < amount:
            return 'Insufficient funds'
        else:
            balance -= amount
            return balance

    return bank

def make_joint(withdraw, old_pass, new_pass):
    """Return a password-protected withdraw function that has joint access to
    the balance of withdraw.

    >>> w = make_withdraw(100, 'hax0r')
    >>> w(25, 'hax0r')
    75
    >>> make_joint(w, 'my', 'secret')
    'Incorrect password'
    >>> j = make_joint(w, 'hax0r', 'secret')
    >>> w(25, 'secret')
    'Incorrect password'
    >>> j(25, 'secret')
    50
    >>> j(25, 'hax0r')
    25
    >>> j(100, 'secret')
    'Insufficient funds'

    >>> j2 = make_joint(j, 'secret', 'code')
    >>> j2(5, 'code')
    20
    >>> j2(5, 'secret')
    15
    >>> j2(5, 'hax0r')
    10

    >>> j2(25, 'password')
    'Incorrect password'
    >>> j2(5, 'secret')
    "Frozen account. Attempts: ['my', 'secret', 'password']"
    >>> j(5, 'secret')
    "Frozen account. Attempts: ['my', 'secret', 'password']"
    >>> w(5, 'hax0r')
    "Frozen account. Attempts: ['my', 'secret', 'password']"
    >>> make_joint(w, 'hax0r', 'hello')
    "Frozen account. Attempts: ['my', 'secret', 'password']"
    """
    "*** YOUR CODE HERE ***"
    check = withdraw(0, old_pass)
    if type(check) == str:
        return check
    def joint(amount, passwd):
        if passwd == new_pass:
            return withdraw(amount, old_pass)
        return withdraw(amount, passwd)
    return joint