[CS61A]HW 05

HW05: http://gaotx.com/cs61a/hw/hw05/
My solution: http://gaotx.com/blogs/2015/05/16/cs61a-hw05/

新鲜的帖子   把以前做的先交了

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

    >>> w = make_withdraw(100, 'hax0r')
    >>> w(25, 'hax0r')
    75
    >>> w(90, 'hax0r')
    'Insufficient funds'
    >>> w(25, 'hwat')
    'Incorrect password'
    >>> w(25, 'hax0r')
    50
    >>> w(75, 'a')
    'Incorrect password'
    >>> w(10, 'hax0r')
    40
    >>> w(20, 'n00b')
    'Incorrect password'
    >>> w(10, 'hax0r')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    >>> w(10, 'l33t')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    """
    "*** YOUR CODE HERE ***"
    def withdraw(amount, pass_word):
        attempts = []
        nonlocal balance   
        if len(attempts) == 3:
            return 'Your account is locked. Attempts: ' + str(attempts)
        if password != pass_word:
            attempts.append(pass_word)
            return 'Incorrect password'
        if amount > balance:
            return 'Insufficient funds'
        balance = balance - amount
        return balance
    return withdraw

def make_joint(withdraw, old_password, new_password):
    """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')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> j(5, 'secret')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> w(5, 'hax0r')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> make_joint(w, 'hax0r', 'hello')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    """
    "*** YOUR CODE HERE ***"
    result = withdraw(0, old_password)
    if type(result) == str:
        return result   
    def join(amount, pass_attempt):
        if pass_attempt == new_password:
            return withdraw(amount, old_password)
        return withdraw(amount, new_password)
    return join

class VendingMachine:
    """A vending machine that vends some product for some price.

    >>> v = VendingMachine('candy', 10)
    >>> v.vend()
    'Machine is out of stock.'
    >>> v.restock(2)
    'Current candy stock: 2'
    >>> v.vend()
    'You must deposit $10 more.'
    >>> v.deposit(7)
    'Current balance: $7'
    >>> v.vend()
    'You must deposit $3 more.'
    >>> v.deposit(5)
    'Current balance: $12'
    >>> v.vend()
    'Here is your candy and $2 change.'
    >>> v.deposit(10)
    'Current balance: $10'
    >>> v.vend()
    'Here is your candy.'
    >>> v.deposit(15)
    'Machine is out of stock. Here is your $15.'
    """
    "*** YOUR CODE HERE ***"
    def __init__(self, product, price):
        self.product = product
        self.price = price
        self.stock = 0  
        self.balance = 0
    def restock(self, n):
        self.stock += n
        return 'Current ' + self.product + 'stock: ' + str(self.stock)
    def deposit(self, n):
        if self.stock == 0:
            return 'Machine is out of stock. Here is your $ '  + str(n)
        self.balance += n
        return 'Current balance: $' + str(self.balance)
    def vend(self):
        if self.stock == 0:
            return 'Machine is out of stock.'   
        diff = self.price - self.balance
        if self.balance < self.price:
            return 'You must deposit $' + str(diff) + ' more.'
        message = 'Here is your ' + str(self.product)
        if diff != 0:
            message = message + 'and $' + str(-diff) + ' change'
        self.balance = 0
        self.stock -= 1
        return message + '.'


class MissManners:
    """A container class that only forward messages that say please.

    >>> v = VendingMachine('teaspoon', 10)
    >>> v.restock(2)
    'Current teaspoon stock: 2'
    >>> m = MissManners(v)
    >>> m.ask('vend')
    'You must learn to say please first.'
    >>> m.ask('please vend')
    'You must deposit $10 more.'
    >>> m.ask('please deposit', 20)
    'Current balance: $20'
    >>> m.ask('now will you vend?')
    'You must learn to say please first.'
    >>> m.ask('please hand over a teaspoon')
    'Thanks for asking, but I know not how to hand over a teaspoon'
    >>> m.ask('please vend')
    'Here is your teaspoon and $10 change.'
    >>> really_fussy = MissManners(m)
    >>> really_fussy.ask('deposit', 10)
    'You must learn to say please first.'
    >>> really_fussy.ask('please deposit', 10)
    'Thanks for asking, but I know not how to deposit'
    >>> really_fussy.ask('please please deposit', 10)
    'Thanks for asking, but I know not how to please deposit'
    >>> really_fussy.ask('please ask', 'please deposit', 10)
    'Current balance: $10'
    >>> fussy_three = MissManners(3)
    >>> fussy_three.ask('add', 4)
    'You must learn to say please first.'
    >>> fussy_three.ask('please add', 4)
    'Thanks for asking, but I know not how to add'
    >>> fussy_three.ask('please __add__', 4)
    7
    """
    "*** YOUR CODE HERE ***"
    def __init__(self, obj):
        self.obj = obj
    def ask(self, message, *args):
        if not message.startswith('please '):
            return 'You must learn to say please first.'
        attr = message[len('please '):]
        if not hasattr(self.obj, attr):
            return 'Thanks for asking, but I know not how to ' + attr
        return getattr(self.obj, attr)(*args)

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

    >>> w = make_withdraw(100, 'hax0r')
    >>> w(25, 'hax0r')
    75
    >>> w(90, 'hax0r')
    'Insufficient funds'
    >>> w(25, 'hwat')
    'Incorrect password'
    >>> w(25, 'hax0r')
    50
    >>> w(75, 'a')
    'Incorrect password'
    >>> w(10, 'hax0r')
    40
    >>> w(20, 'n00b')
    'Incorrect password'
    >>> w(10, 'hax0r')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    >>> w(10, 'l33t')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    """
    "*** YOUR CODE HERE ***"
    attempts=[]
    def withdraw(amount,p):
        nonlocal balance,attempts
        if len(attempts)<=3:
           if p==password:
              if amount > balance:
                 return 'Insufficient funds'
              balance = balance - amount
              return balance
           else:
               attempts+=[p]
               return 'Incorrect Password'
        else:
           return "Your account is locked. Attempts: "+str(attempts)
    return withdraw

def make_joint(withdraw, old_password, new_password):
    """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')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> j(5, 'secret')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> w(5, 'hax0r')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> make_joint(w, 'hax0r', 'hello')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    """
    "*** YOUR CODE HERE ***"
    rt = withdraw(0,old_password)
    if type(rt)==str:
       return rt
    def joint_w(amount,p):
       if p==old_password or p == new_password:
          return withdraw(amount,old_password)
       else:
          return withdraw(amount,new_password)
    return joint_w

class VendingMachine:
    """A vending machine that vends some product for some price.

    >>> v = VendingMachine('candy', 10)
    >>> v.vend()
    'Machine is out of stock.'
    >>> v.restock(2)
    'Current candy stock: 2'
    >>> v.vend()
    'You must deposit $10 more.'
    >>> v.deposit(7)
    'Current balance: $7'
    >>> v.vend()
    'You must deposit $3 more.'
    >>> v.deposit(5)
    'Current balance: $12'
    >>> v.vend()
    'Here is your candy and $2 change.'
    >>> v.deposit(10)
    'Current balance: $10'
    >>> v.vend()
    'Here is your candy.'
    >>> v.deposit(15)
    'Machine is out of stock. Here is your $15.'
    """
    "*** YOUR CODE HERE ***"
    def __init__(self, product, price):
        self.product = product
        self.price = price
        self.stock = 0
        self.balance = 0
    stock = 0
    def restock(self,n):
        self.stock+=n
        return 'Current '+self.product+' stock: '+str(self.stock)
    def vend(self):
        if self.stock < 1:
            return 'Machine is out of stock.'
        if self.balance < self.price:
            return 'You must deposit $'+str(self.price-self.balance)+' more.'
        s = 'Here is your '+self.product+'.'
        self.stock-=1
        if self.balance>self.price:
            s = s+' and $'+str(self.balance-self.price)+' change.'
        self.balance-=self.price
        return s
    def deposit(self,n):
        if self.stock<1:
            return 'Machine is out of stock. Here is your $'+str(n)+'.'
        self.balance+=n
        return 'Current balance: $'+str(self.balance)
        
        

class MissManners:
    """A container class that only forward messages that say please.

    >>> v = VendingMachine('teaspoon', 10)
    >>> v.restock(2)
    'Current teaspoon stock: 2'
    >>> m = MissManners(v)
    >>> m.ask('vend')
    'You must learn to say please first.'
    >>> m.ask('please vend')
    'You must deposit $10 more.'
    >>> m.ask('please deposit', 20)
    'Current balance: $20'
    >>> m.ask('now will you vend?')
    'You must learn to say please first.'
    >>> m.ask('please hand over a teaspoon')
    'Thanks for asking, but I know not how to hand over a teaspoon'
    >>> m.ask('please vend')
    'Here is your teaspoon and $10 change.'
    >>> really_fussy = MissManners(m)
    >>> really_fussy.ask('deposit', 10)
    'You must learn to say please first.'
    >>> really_fussy.ask('please deposit', 10)
    'Thanks for asking, but I know not how to deposit'
    >>> really_fussy.ask('please please deposit', 10)
    'Thanks for asking, but I know not how to please deposit'
    >>> really_fussy.ask('please ask', 'please deposit', 10)
    'Current balance: $10'
    >>> fussy_three = MissManners(3)
    >>> fussy_three.ask('add', 4)
    'You must learn to say please first.'
    >>> fussy_three.ask('please add', 4)
    'Thanks for asking, but I know not how to add'
    >>> fussy_three.ask('please __add__', 4)
    7
    """
    "*** YOUR CODE HERE ***"
    def __init__(self,object):
        self.object = object
    def ask(self,message,*args):
        if not message.startswith('please'):
            return  'You must learn to say please first.'
        attrs = message[len('please '):]
        if not hasattr(self.object,attrs):
            return  'Thanks for asking, but I know not how to '+str(attrs)
        return getattr(self.object,attrs)(*args)

Question 1:
def make_withdraw(balance, password):
        attempts = []
        def withdraw(amount, word):
                nonlocal balance
                if len(attempts) == 3:
                        return 'Your account is locked. Attempts:' + str(attempts)
                elif word != password:
                        attempts.append(word)
                        return 'Incorrect password'
                elif amount > balance:
                        return 'Insufficient funds'
                balance -= amount
                return balance
        return withdraw

Question 2:
def make_joint(withdraw, old_password, new_password):
        error = withdraw(0, old_password)
        if type(error) == str:
                return error
        def joint(amount, password_attempt):
                if password_attempt == new_password:
                        return withdraw(amount, old_password)
                return withdraw(amount, password_attempt)
        return joint

Question 3:
class VendingMachine:
        def __init__(self, some_item, item_price):
                self.balance = 0
                self.stock = 0
                self.price = item_price
                self.item = some_item
                self.change = 0
        def restock(self, n):
                self.stock += n
                return 'Current candy stock: ' + str(self.stock)
        def deposit(self, amount):
                if self.stock == 0:
                        return 'Machine is out of stock. Here is your $' + str(amount)
                else:
                        self.balance += amount
                        return 'Current balance: $' + str(self.balance)
        def vend(self):
                if self.stock == 0:
                        return 'Machine is out of stock.'
                else:
                        if self.balance < self.price:
                                return 'You must deposit $' + str(self.price - self.balance) + ' more.'
                        else:
                                self.stock -= 1
                                self.change = self.balance - self.price
                                self.balance = 0
                                if self.change == 0:
                                        return 'Here is your ' + str(self.item) + '.'
                                else:
                                        return  'Here is your ' + str(self.item) + ' and $' + str(self.change) + ' change.'

Question 4:

class MissManners:

                def__init__(self, object):

                                self.object= object

                defask(self, message, *args):

                                magic_word= 'please '

                                ifnot message.startswith(magic_word):

                                                return'You must learn to say please first.'

                                attr= message[len(magic_word):]

                                ifnot hasattr(self.object, attr):

                                                return'Thanks for asking, but I know not how to ' + attr

                                return getattr(self.object, attr)(*args)

边看答案边做的。。。。

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

    >>> w = make_withdraw(100, 'hax0r')
    >>> w(25, 'hax0r')
    75
    >>> w(90, 'hax0r')
    'Insufficient funds'
    >>> w(25, 'hwat')
    'Incorrect password'
    >>> w(25, 'hax0r')
    50
    >>> w(75, 'a')
    'Incorrect password'
    >>> w(10, 'hax0r')
    40
    >>> w(20, 'n00b')
    'Incorrect password'
    >>> w(10, 'hax0r')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    >>> w(10, 'l33t')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    """
    "*** YOUR CODE HERE ***"
    pwds = []
    def withdraw(amount, pwd):
        nonlocal balance
        if len(pwds) == 3:
            return 'Your account is locked. Attempts: ' + str(pwds)
        if pwd != password:
            pwds.append(pwd)
            return 'Incorrect password'
        if amount > balance:
            return 'Insufficient funds'
        balance = balance - amount
        return balance
    return withdraw



def make_joint(withdraw, old_password, new_password):
    """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')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> j(5, 'secret')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> w(5, 'hax0r')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> make_joint(w, 'hax0r', 'hello')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    """
    "*** YOUR CODE HERE ***"
    init = withdraw(0, old_password)
    if type(init) == str:
        return init
    def joint(amount, pwd):
        if pwd == old_password or pwd == new_password:
            return withdraw(amount, old_password)
        return withdraw(amount, pwd)
    return joint


class VendingMachine:
    """A vending machine that vends some product for some price.

    >>> v = VendingMachine('candy', 10)
    >>> v.vend()
    'Machine is out of stock.'
    >>> v.restock(2)
    'Current candy stock: 2'
    >>> v.vend()
    'You must deposit $10 more.'
    >>> v.deposit(7)
    'Current balance: $7'
    >>> v.vend()
    'You must deposit $3 more.'
    >>> v.deposit(5)
    'Current balance: $12'
    >>> v.vend()
    'Here is your candy and $2 change.'
    >>> v.deposit(10)
    'Current balance: $10'
    >>> v.vend()
    'Here is your candy.'
    >>> v.deposit(15)
    'Machine is out of stock. Here is your $15.'
    """
    "*** YOUR CODE HERE ***"
    def _init_(self, product, price):
        self.product = product
        self.price = price
        self.stock = 0
        self.balance = 0

    def restock(self, n):
        self.stock += n
        return 'Current ' + self.product + 'stock ' + str(self.stock)

    def vend(self):
        if self.stock < 1:
            return 'Machine is out of stock'
        if self.balance < self.price:
            return 'You must deposit $ ' + str(self.price - self.balance) + ' more.'

        msg = 'Here is your ' + self.product + '.'
        self.stock -= 1
        if self.balance > self.price:
            msg = 'Here is your ' + self.product + 'and $ ' + str(self.balance - self.price) + 'change.'
        else:
            msg = 'Here is your ' + self.product + '.'
        self.balance = 0
        return msg

    def deposit(self, amount):
        if self.stock < 1:
            return 'Machine is out of stock. Here is your $ ' + str(amount) + '.'
        self.balance += amount
        return 'Current balance: $ ' + str(self.balance)



class MissManners:
    """A container class that only forward messages that say please.

    >>> v = VendingMachine('teaspoon', 10)
    >>> v.restock(2)
    'Current teaspoon stock: 2'
    >>> m = MissManners(v)
    >>> m.ask('vend')
    'You must learn to say please first.'
    >>> m.ask('please vend')
    'You must deposit $10 more.'
    >>> m.ask('please deposit', 20)
    'Current balance: $20'
    >>> m.ask('now will you vend?')
    'You must learn to say please first.'
    >>> m.ask('please hand over a teaspoon')
    'Thanks for asking, but I know not how to hand over a teaspoon'
    >>> m.ask('please vend')
    'Here is your teaspoon and $10 change.'
    >>> really_fussy = MissManners(m)
    >>> really_fussy.ask('deposit', 10)
    'You must learn to say please first.'
    >>> really_fussy.ask('please deposit', 10)
    'Thanks for asking, but I know not how to deposit'
    >>> really_fussy.ask('please please deposit', 10)
    'Thanks for asking, but I know not how to please deposit'
    >>> really_fussy.ask('please ask', 'please deposit', 10)
    'Current balance: $10'
    >>> fussy_three = MissManners(3)
    >>> fussy_three.ask('add', 4)
    'You must learn to say please first.'
    >>> fussy_three.ask('please add', 4)
    'Thanks for asking, but I know not how to add'
    >>> fussy_three.ask('please __add__', 4)
    7
    """
    "*** YOUR CODE HERE ***"
    def _init_(self, obj):
        self.obj = obj

    def ask(self, msg, *args):
        word = 'please'
        if not msg.startwith(word):
            return 'You mush learn to say please first'
        attr = msg[len(word):]
        if not hasattr(self.obj, attr):
            return 'Thanks for asking, but I know not how to ' + attr
        return getattr(self.obj, attr)(*args)

第四题真心不会做，startwith是什么鬼，其余的都做出来了，代码如下：
#hw05
#Q1
def make_withdraw(balance, password):
    """Return a password-protected withdraw function.

    >>> w = make_withdraw(100, 'hax0r')
    >>> w(25, 'hax0r')
    75
    >>> w(90, 'hax0r')
    'Insufficient funds'
    >>> w(25, 'hwat')
    'Incorrect password'
    >>> w(25, 'hax0r')
    50
    >>> w(75, 'a')
    'Incorrect password'
    >>> w(10, 'hax0r')
    40
    >>> w(20, 'n00b')
    'Incorrect password'
    >>> w(10, 'hax0r')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    >>> w(10, 'l33t')
    "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    """
    "*** YOUR CODE HERE ***"
    l = [password]
    password_wrong =[]

    def withdraw(amount,password_att):
        nonlocal balance
        # nonlocal password
        if len(password_wrong) < 3:        
            if password_att in l:
                if amount > balance:
                    return 'Insufficient funds'
                balance = balance - amount
                return balance
            if password_att not in l:
                # if len(password_wrong) < 3:        
                password_wrong.append(password_att)
                print ("'Incorrect password'")
        else:
            print ("Your account is locked. Attempts: " + '[' + str(password_wrong[0]) +
                    ', ' + password_wrong[1] + ', ' + password_wrong[2] + ']')
    return withdraw

#Q2
def make_joint(withdraw, old_password, new_password):
    """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')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> j(5, 'secret')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> w(5, 'hax0r')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    >>> make_joint(w, 'hax0r', 'hello')
    "Your account is locked. Attempts: ['my', 'secret', 'password']"
    """
    "*** YOUR CODE HERE ***"
    if type(withdraw(0, old_password)) == str:
        return withdraw(0, old_password)
    def join_account(amount, password):
        if password == new_password:
            password = old_password
        return withdraw(amount, password)
    return join_account


#Q3
class VendingMachine:
    """A vending machine that vends some product for some price.

    >>> v = VendingMachine('candy', 10)
    >>> v.vend()
    'Machine is out of stock.'
    >>> v.restock(2)
    'Current candy stock: 2'
    >>> v.vend()
    'You must deposit $10 more.'
    >>> v.deposit(7)
    'Current balance: $7'
    >>> v.vend()
    'You must deposit $3 more.'
    >>> v.deposit(5)
    'Current balance: $12'
    >>> v.vend()
    'Here is your candy and $2 change.'
    >>> v.deposit(10)
    'Current balance: $10'
    >>> v.vend()
    'Here is your candy.'
    >>> v.deposit(15)
    'Machine is out of stock. Here is your $15.'
    """
    "*** YOUR CODE HERE ***"
    def __init__(self, product_name, price):
        self.stock = 0
        self.name = product_name
        self.price = price
        self.balance = 0

    def vend(self):
        if self.stock == 0:
            return 'Machine is out of stock.'
        if self.stock > 0:
            if self.balance < self.price:
                print("You must deposit $" + str(self.price - self.balance) + " more.")
            if self.balance > self.price:
                print("Here is your " + str(self.name) + " and $"
                    + str(self.balance - self.price) + " change.")
                self.balance = 0
                self.stock -= 1
            if self.balance == self.price:
                self.balance = 0
                print("Here is your " + str(self.name) + '.')
                self.stock -= 1
               
    def restock(self, x):
        self.stock += x
        print("Current " + str(self.name) + " stock: " + str(self.stock))
        
    def deposit(self, x):
        if self.stock == 0:
            print("Machine is out of stock. Here is your $" + str(x))
        else:
            self.balance += x
            print("Current balance: $" + str(self.balance))
#Q4
class MissManners:
    """A container class that only forward messages that say please.

    >>> v = VendingMachine('teaspoon', 10)
    >>> v.restock(2)
    'Current teaspoon stock: 2'
    >>> m = MissManners(v)
    >>> m.ask('vend')
    'You must learn to say please first.'
    >>> m.ask('please vend')
    'You must deposit $10 more.'
    >>> m.ask('please deposit', 20)
    'Current balance: $20'
    >>> m.ask('now will you vend?')
    'You must learn to say please first.'
    >>> m.ask('please hand over a teaspoon')
    'Thanks for asking, but I know not how to hand over a teaspoon'
    >>> m.ask('please vend')
    'Here is your teaspoon and $10 change.'
    >>> really_fussy = MissManners(m)
    >>> really_fussy.ask('deposit', 10)
    'You must learn to say please first.'
    >>> really_fussy.ask('please deposit', 10)
    'Thanks for asking, but I know not how to deposit'
    >>> really_fussy.ask('please please deposit', 10)
    'Thanks for asking, but I know not how to please deposit'
    >>> really_fussy.ask('please ask', 'please deposit', 10)
    'Current balance: $10'
    >>> fussy_three = MissManners(3)
    >>> fussy_three.ask('add', 4)
    'You must learn to say please first.'
    >>> fussy_three.ask('please add', 4)
    'Thanks for asking, but I know not how to add'
    >>> fussy_three.ask('please __add__', 4)
    7
    """
    "*** YOUR CODE HERE ***"
    def __init__(self, object):
        self.object = object

    def ask(self, message, *args):
        magic_word = 'please '
        if not message.startswith(magic_word):
            return 'You must learn to say please first.'
        attr = message[len(magic_word):]
        if not hasattr(self.object, attr):
            return 'Thanks for asking, but I know not how to ' + attr
        return getattr(self.object, attr)(*args)

完成作业。。。感觉难度越来越高了。。。。伯克利太吊了，很难想象这是他们第一门编程课。。。。

代码：

1. def make_withdraw(balance, password):
   
2.     """Return a password-protected withdraw function.
   
3. 
   
4.     >>> w = make_withdraw(100, 'hax0r')
   
5.     >>> w(25, 'hax0r')
   
6.     75
   
7.     >>> w(90, 'hax0r')
   
8.     'Insufficient funds'
   
9.     >>> w(25, 'hwat')
   
10.     'Incorrect password'
    
11.     >>> w(25, 'hax0r')
    
12.     50
    
13.     >>> w(75, 'a')
    
14.     'Incorrect password'
    
15.     >>> w(10, 'hax0r')
    
16.     40
    
17.     >>> w(20, 'n00b')
    
18.     'Incorrect password'
    
19.     >>> w(10, 'hax0r')
    
20.     "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    
21.     >>> w(10, 'l33t')
    
22.     "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    
23.     """
    
24.     wrong_pwd_lst = []
    
25.     def withdraw(amount, pwd):
    
26.         nonlocal balance
    
27.         if len(wrong_pwd_lst) == 3:
    
28.             return "Your account is locked. Attempts: " +  str(wrong_pwd_lst)
    
29.         elif pwd != password:
    
30.             wrong_pwd_lst.append(pwd)
    
31.             return "Incorrect password"
    
32.         elif amount > balance:
    
33.             return "Insufficient funds"
    
34.         balance -= amount
    
35.         return balance
    
36.     return withdraw
    
37. 
    
38. 
    
39. def make_joint(withdraw, old_password, new_password):
    
40.     """Return a password-protected withdraw function that has joint access to
    
41.     the balance of withdraw.
    
42. 
    
43.     >>> w = make_withdraw(100, 'hax0r')
    
44.     >>> w(25, 'hax0r')
    
45.     75
    
46.     >>> make_joint(w, 'my', 'secret')
    
47.     'Incorrect password'
    
48.     >>> j = make_joint(w, 'hax0r', 'secret')
    
49.     >>> w(25, 'secret')
    
50.     'Incorrect password'
    
51.     >>> j(25, 'secret')
    
52.     50
    
53.     >>> j(25, 'hax0r')
    
54.     25
    
55.     >>> j(100, 'secret')
    
56.     'Insufficient funds'
    
57. 
    
58.     >>> j2 = make_joint(j, 'secret', 'code')
    
59.     >>> j2(5, 'code')
    
60.     20
    
61.     >>> j2(5, 'secret')
    
62.     15
    
63.     >>> j2(5, 'hax0r')
    
64.     10
    
65. 
    
66.     >>> j2(25, 'password')
    
67.     'Incorrect password'
    
68.     >>> j2(5, 'secret')
    
69.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
70.     >>> j(5, 'secret')
    
71.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
72.     >>> w(5, 'hax0r')
    
73.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
74.     >>> make_joint(w, 'hax0r', 'hello')
    
75.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
76.     """
    
77.     def joint(amount, pwd):
    
78.         if pwd == new_password:
    
79.             return withdraw(amount, old_password)
    
80.         return withdraw(amount, pwd)
    
81. 
    
82.     operation = withdraw(0, old_password)
    
83.     if type(operation) != str:
    
84.         return joint
    
85.     else:
    
86.         return operation
    
87. 
    
88. 
    
89. class VendingMachine:
    
90.     """A vending machine that vends some product for some price.
    
91. 
    
92.     >>> v = VendingMachine('candy', 10)
    
93.     >>> v.vend()
    
94.     'Machine is out of stock.'
    
95.     >>> v.restock(2)
    
96.     'Current candy stock: 2'
    
97.     >>> v.vend()
    
98.     'You must deposit $10 more.'
    
99.     >>> v.deposit(7)
    
100.     'Current balance: $7'
     
101.     >>> v.vend()
     
102.     'You must deposit $3 more.'
     
103.     >>> v.deposit(5)
     
104.     'Current balance: $12'
     
105.     >>> v.vend()
     
106.     'Here is your candy and $2 change.'
     
107.     >>> v.deposit(10)
     
108.     'Current balance: $10'
     
109.     >>> v.vend()
     
110.     'Here is your candy.'
     
111.     >>> v.deposit(15)
     
112.     'Machine is out of stock. Here is your $15.'
     
113.     """
     
114.     def __init__(self, kind, price):
     
115.         """Constructor"""
     
116.         self.kind = kind
     
117.         self.price = price
     
118.         self.amount = 0
     
119.         self.change = 0
     
120. 
     
121.     def deposit(self, cash):
     
122.         """deposit change into the vending machine"""
     
123.         self.change += cash
     
124.         if self.amount == 0:
     
125.             return self.vend() + " Here is your $%s." % (self.change)
     
126.         return "Current balance: $%d" % (self.change)
     
127. 
     
128.     def vend(self):
     
129.         """vend one item if meet the requirement"""
     
130.         if self.amount == 0:
     
131.             return "Machine is out of stock."
     
132.         elif self.change < self.price:
     
133.             return "You must deposit $%d more." % (self.price - self.change)
     
134.         cash_back = self.change - self.price
     
135.         self.amount -= 1
     
136.         self.change = 0
     
137.         ret_str = "Here is your %s." % (self.kind)
     
138.         if cash_back != 0:
     
139.             ret_str = ret_str[:-1] + " and $%d change." % (cash_back)
     
140.         return ret_str
     
141. 
     
142.     def restock(self, amount):
     
143.         """Refill the vending machine"""
     
144.         self.amount += amount
     
145.         return "Current %s stock: %d"  % (self.kind, self.amount)
     
146. 
     
147. 
     
148. class MissManners:
     
149.     """A container class that only forward messages that say please.
     
150. 
     
151.     >>> v = VendingMachine('teaspoon', 10)
     
152.     >>> v.restock(2)
     
153.     'Current teaspoon stock: 2'
     
154.     >>> m = MissManners(v)
     
155.     >>> m.ask('vend')
     
156.     'You must learn to say please first.'
     
157.     >>> m.ask('please vend')
     
158.     'You must deposit $10 more.'
     
159.     >>> m.ask('please deposit', 20)
     
160.     'Current balance: $20'
     
161.     >>> m.ask('now will you vend?')
     
162.     'You must learn to say please first.'
     
163.     >>> m.ask('please hand over a teaspoon')
     
164.     'Thanks for asking, but I know not how to hand over a teaspoon'
     
165.     >>> m.ask('please vend')
     
166.     'Here is your teaspoon and $10 change.'
     
167.     >>> really_fussy = MissManners(m)
     
168.     >>> really_fussy.ask('deposit', 10)
     
169.     'You must learn to say please first.'
     
170.     >>> really_fussy.ask('please deposit', 10)
     
171.     'Thanks for asking, but I know not how to deposit'
     
172.     >>> really_fussy.ask('please please deposit', 10)
     
173.     'Thanks for asking, but I know not how to please deposit'
     
174.     >>> really_fussy.ask('please ask', 'please deposit', 10)
     
175.     'Current balance: $10'
     
176.     >>> fussy_three = MissManners(3)
     
177.     >>> fussy_three.ask('add', 4)
     
178.     'You must learn to say please first.'
     
179.     >>> fussy_three.ask('please add', 4)
     
180.     'Thanks for asking, but I know not how to add'
     
181.     >>> fussy_three.ask('please __add__', 4)
     
182.     7
     
183.     """
     
184.     def __init__(self, vm):
     
185.         self.vm = vm
     
186. 
     
187.     def ask(self, message, *args):
     
188.         if len(message) < 6 or message[:6] != "please":
     
189.             return "You must learn to say please first."
     
190.         method = message[7:]    # split
     
191.         # check if the method is callable
     
192.         if hasattr(self.vm, method) and callable(getattr(self.vm, method)):
     
193.             return getattr(self.vm, method)(*args)
     
194.         else:
     
195.             return "Thanks for asking, but I know not how to %s" % (method)
     

复制代码

1. def make_withdraw(balance, password):
   
2.     """Return a password-protected withdraw function.
   
3. 
   
4.     >>> w = make_withdraw(100, 'hax0r')
   
5.     >>> w(25, 'hax0r')
   
6.     75
   
7.     >>> w(90, 'hax0r')
   
8.     'Insufficient funds'
   
9.     >>> w(25, 'hwat')
   
10.     'Incorrect password'
    
11.     >>> w(25, 'hax0r')
    
12.     50
    
13.     >>> w(75, 'a')
    
14.     'Incorrect password'
    
15.     >>> w(10, 'hax0r')
    
16.     40
    
17.     >>> w(20, 'n00b')
    
18.     'Incorrect password'
    
19.     >>> w(10, 'hax0r')
    
20.     "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    
21.     >>> w(10, 'l33t')
    
22.     "Your account is locked. Attempts: ['hwat', 'a', 'n00b']"
    
23.     """
    
24.     "*** YOUR CODE HERE ***"
    
25.     incor_password = []
    
26.     def withdraw(amount, input_password):
    
27.         nonlocal balance
    
28.         if len(incor_password) == 3:
    
29.             return 'Your account is locked. Attempts: '+ str(incor_password[:])
    
30.         elif input_password != password:
    
31.             incor_password.append(input_password)
    
32.             return 'Incorrect password'
    
33.         else:
    
34.             if amount <= balance:
    
35.                 balance = balance - amount
    
36.                 return balance
    
37.             else:
    
38.                 return 'Insufficient funds'
    
39.     return withdraw
    
40. 
    
41. 
    
42. def make_joint(withdraw, old_password, new_password):
    
43.     """Return a password-protected withdraw function that has joint access to
    
44.     the balance of withdraw.
    
45. 
    
46.     >>> w = make_withdraw(100, 'hax0r')
    
47.     >>> w(25, 'hax0r')
    
48.     75
    
49.     >>> make_joint(w, 'my', 'secret')
    
50.     'Incorrect password'
    
51.     >>> j = make_joint(w, 'hax0r', 'secret')
    
52.     >>> w(25, 'secret')
    
53.     'Incorrect password'
    
54.     >>> j(25, 'secret')
    
55.     50
    
56.     >>> j(25, 'hax0r')
    
57.     25
    
58.     >>> j(100, 'secret')
    
59.     'Insufficient funds'
    
60. 
    
61.     >>> j2 = make_joint(j, 'secret', 'code')
    
62.     >>> j2(5, 'code')
    
63.     20
    
64.     >>> j2(5, 'secret')
    
65.     15
    
66.     >>> j2(5, 'hax0r')
    
67.     10
    
68. 
    
69.     >>> j2(25, 'password')
    
70.     'Incorrect password'
    
71.     >>> j2(5, 'secret')
    
72.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
73.     >>> j(5, 'secret')
    
74.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
75.     >>> w(5, 'hax0r')
    
76.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
77.     >>> make_joint(w, 'hax0r', 'hello')
    
78.     "Your account is locked. Attempts: ['my', 'secret', 'password']"
    
79.     """
    
80.     "*** YOUR CODE HERE ***"
    
81.     initial_try = withdraw(0, old_password)
    
82.     if type(initial_try) == str:
    
83.         return initial_try
    
84.     def joint(amount, set_new_password):
    
85.         if set_new_password == new_password:
    
86.             return withdraw(amount, old_password)
    
87.         else:
    
88.             return withdraw(amount, set_new_password)
    
89.     return joint
    
90. 
    
91. class VendingMachine:
    
92.     """A vending machine that vends some product for some price.
    
93. 
    
94.     >>> v = VendingMachine('candy', 10)
    
95.     >>> v.vend()
    
96.     'Machine is out of stock.'
    
97.     >>> v.restock(2)
    
98.     'Current candy stock: 2'
    
99.     >>> v.vend()
    
100.     'You must deposit $10 more.'
     
101.     >>> v.deposit(7)
     
102.     'Current balance: $7'
     
103.     >>> v.vend()
     
104.     'You must deposit $3 more.'
     
105.     >>> v.deposit(5)
     
106.     'Current balance: $12'
     
107.     >>> v.vend()
     
108.     'Here is your candy and $2 change.'
     
109.     >>> v.deposit(10)
     
110.     'Current balance: $10'
     
111.     >>> v.vend()
     
112.     'Here is your candy.'
     
113.     >>> v.deposit(15)
     
114.     'Machine is out of stock. Here is your $15.'
     
115.     """
     
116.     "*** YOUR CODE HERE ***"
     
117.     def __init__(self, product, price):
     
118.         self.stock = 0
     
119.         self.balance = 0
     
120.         self.price = price
     
121.         self.product = product
     
122.     def vend(self):
     
123.         if self.stock == 0:
     
124.             if self.balance == 0:
     
125.                 return 'Machine is out of stock.'
     
126.             else:
     
127.                 return 'Machine is out of stock. Here is your $' + str(self.balance) + '.'
     
128.         elif self.balance < self.price:
     
129.             return 'You must deposit $' + str(self.price - self.balance) + ' more.'
     
130.         elif self.balance > self.price:
     
131.             change = self.balance - self.price
     
132.             self.balance =0
     
133.             self.stock -= 1
     
134.             return 'Here is your ' + str(self.product) + ' and $' + str(change) + ' change.'
     
135.         else:
     
136.             self.balance =0
     
137.             self.stock -= 1
     
138.             return 'Here is your ' + str(self.product) + '.'
     
139.     def restock(self, number):
     
140.         self.stock += number
     
141.         return 'Current ' + str(self.product) + ' stock: '+ str(self.stock)
     
142.     def deposit(self, money):
     
143.         self.balance += money
     
144.         if self.stock == 0:
     
145.             return 'Machine is out of stock. Here is your $' + str(self.balance) + '.'
     
146.         return 'Current balance: $' + str(self.balance)
     
147. 
     
148. class MissManners:
     
149.     """A container class that only forward messages that say please.
     
150. 
     
151.     >>> v = VendingMachine('teaspoon', 10)
     
152.     >>> v.restock(2)
     
153.     'Current teaspoon stock: 2'
     
154.     >>> m = MissManners(v)
     
155.     >>> m.ask('vend')
     
156.     'You must learn to say please first.'
     
157.     >>> m.ask('please vend')
     
158.     'You must deposit $10 more.'
     
159.     >>> m.ask('please deposit', 20)
     
160.     'Current balance: $20'
     
161.     >>> m.ask('now will you vend?')
     
162.     'You must learn to say please first.'
     
163.     >>> m.ask('please hand over a teaspoon')
     
164.     'Thanks for asking, but I know not how to hand over a teaspoon'
     
165.     >>> m.ask('please vend')
     
166.     'Here is your teaspoon and $10 change.'
     
167.     >>> really_fussy = MissManners(m)
     
168.     >>> really_fussy.ask('deposit', 10)
     
169.     'You must learn to say please first.'
     
170.     >>> really_fussy.ask('please deposit', 10)
     
171.     'Thanks for asking, but I know not how to deposit'
     
172.     >>> really_fussy.ask('please please deposit', 10)
     
173.     'Thanks for asking, but I know not how to please deposit'
     
174.     >>> really_fussy.ask('please ask', 'please deposit', 10)
     
175.     'Current balance: $10'
     
176.     >>> fussy_three = MissManners(3)
     
177.     >>> fussy_three.ask('add', 4)
     
178.     'You must learn to say please first.'
     
179.     >>> fussy_three.ask('please add', 4)
     
180.     'Thanks for asking, but I know not how to add'
     
181.     >>> fussy_three.ask('please __add__', 4)
     
182.     7
     
183.     """
     
184.     "*** YOUR CODE HERE ***"
     
185.     def __init__(self, object):
     
186.         self.object = object
     
187.     def ask(self, message, *args):
     
188.         if not message.startswith('please'):
     
189.             return 'You must learn to say please first.'
     
190.         info = message[len('please '):]
     
191.         if not hasattr(self.object, info):
     
192.             return 'Thanks for asking, but I know not how to ' + str(info)
     
193.         return getattr(self.object, info)(*args)

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