Introduction to Computer Science and Programming in Python

Lecture 8

1. Class Definition

   Which of the following is a good and valid definition for a class representing a car?

   def class Car(object): close

   class Car(object): check

   def Car(object): close

   class A(object) close

   Check   Show Solution

2. Class Instance

   Using the class definition below, which line creates a new Car object with 4 wheels and 2 doors?

   class Car(object):
       def __init__(self, w, d):
           self.wheels = w
           self.doors = d
           self.color = ""
   

   Car(mycar, 4, 2) close

   mycar = Car(4, 2, “white”) close

   mycar = Car(4, 2) check

   mycar = Car(2, 4) close

   Check   Show Solution

3. Methods

   Which of the following methods changes the color of the car, based on the definition below?

   class Car(object):
       def __init__(self, w, d):
           self.wheels = w
           self.doors = d
           self.color = ""
   

   def paint(c):
       color = c
   

   close

   def paint(self, c):
       color = c
   

   close

   def paint(c):
       self.c = c
   

   close

   def paint(self, c):
       self.color = c
   

   check

   Check   Show Solution

4. Method Call

   You create a car with mycar = Car(4, 2). Which is a line of code to change the color of mycar to “red”?

   class Car(object):
       def __init__(self, w, d):
           self.wheels = w
           self.doors = d
           self.color = ""
       def paint(self, c):
           self.color = c
   

   Car.paint(“red”) close

   mycar.paint(red) close

   mycar.paint(“red”) check

   mycar.paint(Car, “red”) close

   Check   Show Solution

5. Special Methods

   With the code below, what does the line print(mycar == yourcar) print?

   class Car(object):
       def __init__(self, w, d):
           self.wheels = w
           self.doors = d
           self.color = ""
       def paint(self, c):
           self.color = c
       def __eq__(self, other):
           if self.wheels == other.wheels and \
               self.color == other.color and \
               self.doors == other.doors:
               return True
           else:
               return False
   
   mycar = Car(4, 2)
   mycar.paint("red")
   yourcar = Car(4,2)
   print(mycar == yourcar)
   

   True close

   False check

   An error close

   Check   Show Solution