Lecture 9

Getters and Setters

Which of the below is a getter method for the number of wheels?
```
----------------------------------
----------- Given ------------
----------------------------------
class Car(object):
    def __init__(self, w, d):
        self.wheels = w
        self.doors = d
        self.color = ""
----------------------------------

(A)    def get_wheels():
             return wheels

(B)    def get_wheels():
             return self.wheels

(C)    def get_wheels(self):
             return wheels

(D)    def get_wheels(self):
             return self.wheels
```
Exercise 1
 
def get_wheels(): return wheels
 
def get_wheels(): return self.wheels
 
def get_wheels(self): return wheels
 
def get_wheels(self): return self.wheels
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Subclass

Whate line could replace ____blank____ to create a class that inherets from Animal in the code below?
```
____blank____
    def speak(self):
        print("ruff ruff")

(line1) d = Dog(7)
(line2) d.set_name("Ruffles")
(line3) d.speak()
```
Exercise 2
 class Dog(Animal):

 class Animal(Dog):

 class Dog(object)

With this definition of Dog, you run a program with line1, line2, and line3 above. What happens? Refer to the lecture slides for the code making up the "Animal" class.

Error on (line1) because Dog does not have an __init__

Uses the __init__ from Animal, but then an error (line2) because Dog does not have a set_name method.

Uses the __init__ and set_name from Animal, but then an error (line3) because all methods must return something.

Runs, creates a Dog object with age=7 and name="Ruffles", and prints "ruff ruff"

Lecture 9

Getters and Setters

Subclass