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

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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

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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

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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

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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

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