Question

Python: Design a Ship class that has the following members: A member variable for the name of the ship. A member variable for the year that the ship was built. An init method and appropriate accessors and mutators. A print function that displays the ship’s name and the year it was built. Design a CruiseShip class that is derived from the Ship class. The CruiseShip class should have the following members: A member variable for the maximum number of passengers. An init method and appropriate accessors and mutators. A print function that overrides the print function in the base class. The CruiseShip class’s print function should display only the ship’s name and the maximum number of passengers. Design a CargoShip class that is derived from the Ship class. The CargoShip class should have the following members: A member variable for the cargo capacity in tonnage. An init method and appropriate accessors and mutators. A print function that overrides the print function in the base class. The CargoShip class’s print function should display only the ship’s name and the ship’s cargo capacity. Demonstrate the classes in a program that has a list of Ships. The list elements should be initialized with Ship, CruiseShip, and CargoShip objects. The program should then step through the list, calling each object’s print function. Use the Python issinstance() function to determine which object type each element holds.

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change or if you get any indentation issues. If you are satisfied with the solution, please rate the answer. Thanks

#code

#Ship class
class Ship:
    #constructor with default values for name and year (not important to pass values)
    def __init__(self,name='',year=1900):
        #assigning values to name and year fields
        self.__name=name
        self.__year=year
  
    #getters and setters for all attributes
   
    def getName(self):
        return self.__name

    def setName(self,name):
        self.__name=name

    def getYear(self):
        return self.__year

    def setYear(self,year):
        self.__year=year
   
    #print method to print the ship name and year
    def print(self):
        print('Name:',self.__name,',Year:',self.__year)


#CruiseShip class
class CruiseShip(Ship):
    #constructor taking default values for name and max passengers
    def __init__(self,name='',max_passengers=0):
        #setting __maximum_passengers
        self.__maximum_passengers=max_passengers
        #setting name using mutator for name
        self.setName(name)
   
    #getter and setter
   
    def getMaximumPassengers(self):
        return self.__maximum_passengers

    def setMaximumPassengers(self, passengers):
        self.__maximum_passengers=passengers
   
    #prints the ship name and maximum passengers
    def print(self):
        print('Name:', self.getName(), ',Maximum number of passengers:', self.__maximum_passengers)

#CargoShip class
class CargoShip(Ship):
    # constructor taking default values for name and max capacity
    def __init__(self,name='',capacity=0):
        self.__capacity=0
        self.setName(name)

    def getCapacity(self):
        return self.__capacity

    def setCapacity(self,capacity):
        self.__capacity=capacity

    # prints the ship name and maximum capaity
    def print(self):
        print('Name:', self.getName(), ',Maximum capacity (tonnage):', self.__capacity)


#main program for testing
if __name__ == '__main__':
    #creating an empty list
    ships_list=[]
    #adding instances of Ship, CruiseShip and CargoShip
    ships_list.append(Ship('Queen',1983))
    ships_list.append(Ship('ABC-1',2000))
    ships_list.append(CruiseShip('Gambit',600))
    ships_list.append(CruiseShip('Octavia',799))
    ships_list.append(CargoShip('Omega',450000))
    ships_list.append(CargoShip('Gladiator',125000))
    #looping through ships_list
    for i in ships_list:
        #calling print method
        i.print()
        #finding type using isinstance, and displaying it too
        print('(Type: ',end='')
        if isinstance(i,CruiseShip):
            print('CruiseShip)')
        elif isinstance(i,CargoShip):
            print('CargoShip)')
        else:
            print('Ship)')

#output

Name: Queen ,Year: 1983

(Type: Ship)

Name: ABC-1 ,Year: 2000

(Type: Ship)

Name: Gambit ,Maximum number of passengers: 600

(Type: CruiseShip)

Name: Octavia ,Maximum number of passengers: 799

(Type: CruiseShip)

Name: Omega ,Maximum capacity (tonnage): 0

(Type: CargoShip)

Name: Gladiator ,Maximum capacity (tonnage): 0

(Type: CargoShip)