Polymorphism through inheritance in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of polymorphic method calls

What is the output of this Python code that uses polymorphism through inheritance?

Python

class Animal:
    def speak(self):
        return "..."

class Dog(Animal):
    def speak(self):
        return "Woof"

class Cat(Animal):
    def speak(self):
        return "Meow"

animals = [Dog(), Cat(), Animal()]
for a in animals:
    print(a.speak())

A Woof\nMeow\nNone

B None\nNone\nNone

C Woof\nMeow\n...

D Woof\nMeow

💡 Hint

Each subclass overrides the speak method. The base class returns '...'.

The Dog and Cat classes override the speak method to return their own sounds. The Animal base class returns '...'. The loop calls speak on each object, printing their respective outputs.

🧠 Conceptual

intermediate

Understanding polymorphism behavior

Which statement best describes polymorphism in the context of inheritance?

A A subclass cannot change any methods from the parent class.

B A subclass can have methods with the same name as the parent class, but different behavior.

C Polymorphism means creating multiple classes with no relation.

D Inheritance prevents method overriding.

💡 Hint

Think about how subclasses can change behavior of inherited methods.

Polymorphism allows subclasses to override methods from the parent class to provide different behavior while sharing the same method name.

🔧 Debug

advanced

Identify the error in polymorphic method call

What error will this code raise when run?

Python

class Vehicle:
    def move(self):
        return "Moving"

class Car(Vehicle):
    def move(self, speed):
        return f"Moving at {speed} km/h"

v = Vehicle()
c = Car()
print(v.move())
print(c.move())

A TypeError: move() missing 1 required positional argument: 'speed'

B AttributeError: 'Car' object has no attribute 'move'

C No error, prints 'Moving' and 'Moving at km/h'

D SyntaxError: invalid syntax

💡 Hint

Check how the move method is defined in Car and how it is called.

The Car class overrides move to require a speed argument. Calling c.move() without arguments causes a TypeError.

❓ Predict Output

advanced

Output of polymorphic method with super()

What is the output of this code using super() in polymorphism?

Python

class Writer:
    def write(self):
        return "Writing text"

class Author(Writer):
    def write(self):
        base = super().write()
        return base + " and publishing books"

a = Author()
print(a.write())

A Writing text and publishing books

B Writing text

C and publishing books

D AttributeError: 'super' object has no attribute 'write'

💡 Hint

super() calls the parent class method.

The Author class calls the parent write method using super(), then adds extra text. The output combines both strings.

🧠 Conceptual

expert

Polymorphism with multiple inheritance method resolution

Given these classes, what will be the output of calling c.action()?

Python

class A:
    def action(self):
        return "Action from A"

class B(A):
    def action(self):
        return "Action from B"

class C(A):
    def action(self):
        return "Action from C"

class D(B, C):
    pass

d = D()
print(d.action())

A Action from A

B Action from C

C TypeError: ambiguous method resolution

D Action from B

💡 Hint

Python uses method resolution order (MRO) from left to right in multiple inheritance.

Class D inherits from B and C. Since B is first, its action method is called. This is Python's MRO behavior.