Question

Lab 10C - Creating a new class

This assignment assumes that you have read and understood the following documents:

http://www.annedawson.net/Python3_Intro_OOP.pdf
http://www.annedawson.net/Python3_Prog_OOP.pdf

and that you're familiar with the following example programs:

http://www.annedawson.net/python3programs.html

13-01.py, 13-02.py, 13-03.py, 13-04.py

Instructions:

Complete as much as you can in the time allowed.

Write a Python class named "Car" that has the following data attributes (please create your own variable names for these attributes using the recommended naming conventions):

- year (for the car's year of manufacture)

- make (for the car's maker)

- model (for the car's model)

- speed (for the car's speed)

The class should have an __init__ method that accepts year, make and model as arguments. These values should be assigned to the object's corresponding attributes. Speed should be set to 0 in the __init__ method.

The class should have a __str__ method that returns the state of the Car object - in other words, it returns a string composed of the values of each of the car object's attributes.

The class should have an accessor method and a mutator method for each attribute - also following the recommended naming conventions.

The class should also have the following three methods:

- a method called stop, which sets the speed of the Car object to 0 and prints the name of the model and the text "stopped" on the same line.

- a method called brake, which reduces the speed by 5 (as long as the speed is greater than 0) and prints the name of the model and the text "slowing down" on the same line.

- a method called accelerate, which increases the speed by 5 and prints the name of the model and the text "speeding up" on the same line.

Each of the methods of the class should have a docstring explaining the purpose of the method.

Write a main program to create two Car objects. The first car should be created with these values: "2014","Toyota","Tacoma", the second car should have these values: "2017","Ford","Focus".

Write one line of code to print the docstring for the class.

Write one line of code to print the state (current attribute values) of the first car object.

Write one line of code to print the state (current attribute values) of the second car object.

Write one line of code to print the docstring of any accessor method.

Write one line of code to print the docstring of any mutator method.

Write one line of code to set the speed of the first Car object to 50

Write one line of code to set the speed of the second Car object to 65

Write one line of code to print the state (current attribute values) of the first car object.

Write one line of code to print the state (current attribute values) of the second car object.

Write one line of code to stop the second Car object.

Write one line of code to print the state (current attribute values) of the first car object.

Write one line of code to print the state (current attribute values) of the second car object.

Write one line of code to accelerate the second Car object.

Write one line of code to brake the first Car object.

Write one line of code to print the state (current attribute values) of the first car object.

Write one line of code to print the state (current attribute values) of the second car object.

Include the recommended comments at the top of the code for filename, programmer, date etc.

Answer 1

'''

Python version : 3.6

Python program to create and implement a class Car

'''

class Car:

               """ Class to define the attributes and function to represent a Car """

              

               def __init__(self,year,make,model):

                              '''Initializes the objects of Car class with the passed values'''

                              self.__year = year

                              self.__make = make

                              self.__model = model

                              self.__speed = 0

                             

               def __str__(self):

                              ''' Returns the string representation of the Car containing the attribute values'''

                              return("Year : "+str(self.__year)+" Make : "+self.__make+" Model : "+self.__model+" Speed : "+str(self.__speed))

                             

               def set_speed(self,speed):

                              """ Function to set the car's speed """

                              self.__speed = speed

                             

               def set_year(self,year):

                              """ Function to set the car's year of manufacture """

                              self.__year = year

                             

               def set_make(self,make):

                              """ Function to set the car's make """

                              self.__make = make

                             

               def set_model(self,model):

                              """ Function to set the car's model """

                              self.__model = model

                             

               def get_speed(self):

                              """ Function to return the car's speed """

                              return self.__speed

                             

               def get_year(self):

                              """ Function to return the car's year of manufacture """

                              return self.__year

               def get_make(self):

                              """ Function to return the car's make """

                              return self.__make

                             

               def get_model(self):

                              """ Function to return car's model """

                              return self.__model

                             

               def stop(self):

                              ''' Function to stop the car i.e set the speed of the car to 0 '''

                              self.__speed = 0

                              print(self.__model + ' stopped ')

              

               def brake(self):

                              ''' Function to apply brakes to the car i.e reduce the speed of the car by 5 '''

                              if self.__speed > 5:

                                             self.__speed = self.__speed - 5

                                             print(self.__model + ' slowing down')

              

               def accelerate(self):

                              ''' Function to accelerate the car i.e increase the speed of the car by 5 '''

                              self.__speed = self.__speed + 5

                              print(self.__model + ' speeding up')

                             

def main():

               # create two Car objects.

               car1 = Car("2014","Toyota","Tacoma")

               car2 = Car("2017","Ford","Focus")

               # print the docstring for the class.

               print(Car.__doc__)

               # print the state (current attribute values) of the first car object and second car object

               print(car1)

               print(car2)

               # print the docstring of any accessor method.

               print(Car.get_make.__doc__)

               # print the docstring of any mutator method.

               print(Car.set_make.__doc__)

               # set the speed of the first Car object to 50

               car1.set_speed(50)

               # set the speed of the second Car object to 65

               car2.set_speed(65)

               # print the state (current attribute values) of the first car object and second car object

               print(car1)

               print(car2)

               # stop the second Car object.

               car2.stop()

               # print the state (current attribute values) of the first car object and second car object

               print(car1)

               print(car2)

               # accelerate the second Car object.

               car2.accelerate()

               # brake the first Car object.

               car1.brake()

               # print the state (current attribute values) of the first car object and second car object

               print(car1)

               print(car2)

              

# call the main method  

if __name__ == "__main__":       

               main()   

                                            

#end of program             

              

Code Screenshot:

Python version 3.6 Python program to create and implement a class Car 2 2 Bclass Car: " Class to define the attributes and function to represent a Car "" def init (self,year,make,model) Initializes the objects of Car class with the passed values'' r self. year = year 10 11 12 13 self. make make self. model= model 14 self speed= 0 15 16 17 18 def (self) Returns the string representation of the Car containing the attribute values'' return ("Year "+str (self. year) +" Make "+self. make+" Model: "+self. model+" Speed "+str (self. speed)) str 19 20 def set speed (self, speed) Function to set the car's speed " 21 22 23 self. speed speed def set year (self, year) "wwFunction to set the car's year of manufacture " self. year= year 24 25 26 27 def set make (self, make) " Function to set the car's make 28 29 30 self. make make 31 def set model (self,model) 32 Function to set the car's model self. model= model 33 34 35 def get speed (self) 36 ion to return the car's speed "" 37 return self. speed 38 39 def get year to return the car's year of manufacture 40 (self) 41 n return self. year

39 def get year (self) "ww Function to return the car's year of manufacture """ return self. year 40 41 42 43 def get make (self) 44 Function to return the car's make 45 46 return self. make 47 def get model (self) un Function to return car's model 48 49 50 return self. model 51 def stop (self): 52 Function to stop the car i.e set the speed of the car to 0 ' self. speed = 0 print (self. model ' 53 54 stopped ' 55 56 def brake (self) 57 Function to apply brakes to the car i.e reduce the speed of the car by 5 ' if self. speed > 5 self. speed self print (self. 58 59 speed 5 model slowing down') 60 61 62 def accelerate (self): 63 Function to accelerate the car i.e increase the speed of the car by 5 self. speed self. speed 5 print (self._model + 64 65 66 speeding up')

67 68 Edef main () 69 70 create two Car objects. carl Car ("2014" , "Toyota","Tacoma") car2 Car ("2017","Ford","Focus") print the docstring for the class. print (Car.doc #print the state (current attribute values) of the first car object and second car object print (car1) print (car2) print the docstring of any accessor me thod. print (Car.get_make. print the docstring of any mutator method. print (Car.set make. set the speed of the first Car object to 50 car1.set_speed (50) # set the speed of the second Car object to 65 car2.set speed (65) print the state (current attribute values) of the first car object and second car object print (car1) print (car2) #stop the second Car object. car2.stop ) # print the state (current attribute values) of the first car object and second car object print (car1) print (car2) accelerate the second Car object. car2.accelerate () #brake the first Car object. car1.brake () 71 72 73 74 75 76 77 78 79 doc) 80 81 82 doc ) 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 print the state (current attribute values) of the first car object and second car object print (car1) print (car2) 99 100 101 call the main method 102 main ": 103 Eif name main ( 104 105 #end of program 106 8ggggg

Output:

Class to define the attributes and function to represent a Car Toyota Model Tacoma Speed 0 Ford Model : Focus Speed Year 2014 Make : 2017 Make : Year 0 Function to return the car's make Function to set the car's make Year : 2014 Make Toyota Model Tacoma Speed 50 Year Focus stopped Year 2014 Make: Year Focus speeding up Tacoma slowing down Year 2014 Make Year Ford Model : Focus Speed : 65 2017 Make Toyota Model : Tacoma Speed Focus Speed 0 : 50 2017 Make Ford Model : Toyota Model: Tacoma Speed: 45 Focus Speed 5 : 2017 Make : Ford Model