Method overriding in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to override the method greet in the child class.

Python

class Parent:
    def greet(self):
        print("Hello from Parent")

class Child(Parent):
    def [1](self):
        print("Hello from Child")

c = Child()
c.greet()

Drag options to blanks, or click blank then click option'

Agreet

Bsay_hello

Chello

Dgreeting

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different method name in the child class.

Forgetting to define the method in the child class.

The child class overrides the method by defining a method with the same name greet.

2fill in blank

medium

Complete the code to call the overridden method from the child class instance.

Python

class Animal:
    def sound(self):
        print("Some sound")

class Dog(Animal):
    def sound(self):
        print("Bark")

pet = Dog()
pet.[1]()

Drag options to blanks, or click blank then click option'

Amake_sound

Bcall_sound

Cnoise

Dsound

Attempts:

3 left

💡 Hint

Common Mistakes

Calling a method name that does not exist.

Using the parent class method name incorrectly.

The method sound is overridden in the Dog class and called on the instance.

3fill in blank

hard

Fix the error in the child class method overriding by completing the method name correctly.

Python

class Vehicle:
    def start(self):
        print("Vehicle started")

class Car(Vehicle):
    def [1](self):
        print("Car started")

my_car = Car()
my_car.start()

Drag options to blanks, or click blank then click option'

Abegin

Brun

Cstart

Dgo

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different method name in the child class.

Not overriding the method at all.

The child class must override the method with the exact same name start to replace the parent method.

4fill in blank

hard

Fill both blanks to override the method and call the parent method inside the child method.

Python

class Writer:
    def write(self):
        print("Writing...")

class Author(Writer):
    def [1](self):
        print("Author starts writing")
        super().[2]()

a = Author()
a.write()

Drag options to blanks, or click blank then click option'

Awrite

Bstart

Dbegin

Attempts:

3 left

💡 Hint

Common Mistakes

Using different method names in override and super call.

Not calling the parent method inside the child method.

The child class overrides write and calls the parent write method using super().

5fill in blank

hard

Fill all three blanks to override the method, call the parent method, and add extra behavior.

Python

class Printer:
    def print_message(self):
        print("Printing message")

class ColorPrinter(Printer):
    def [1](self):
        super().[2]()
        print([3])

cp = ColorPrinter()
cp.print_message()

Drag options to blanks, or click blank then click option'

Aprint_message

C"Printing in color"

D"Color print"

Attempts:

3 left

💡 Hint

Common Mistakes

Using different method names.

Not calling the parent method.

Incorrect string in print statement.

The child class overrides print_message, calls the parent method, and adds a new print statement.

Practice

1.

What is method overriding in Python?

Choose the best description.

easy

A. A child class provides a new version of a method from its parent class.

B. A method that is called automatically when an object is created.

C. A method that cannot be changed once defined in a class.

D. A method that is only accessible inside the class it is defined.

Solution

1. Step 1: Understand method overriding concept

   Method overriding means a child class changes a method from its parent by defining a method with the same name.

2. Step 2: Match description to concept

   A child class provides a new version of a method from its parent class. correctly describes this behavior, while others describe different concepts.

3. Final Answer:

   A child class provides a new version of a method from its parent class. -> Option A

4. Quick Check:

   Method overriding = child changes parent method [OK]

Hint: Child class method with same name replaces parent method [OK]

Common Mistakes:

• Confusing overriding with overloading
• Thinking overriding means creating a new method
• Believing methods cannot be changed in child classes

2.

Which of the following is the correct way to override a method greet in a child class?

class Parent:
    def greet(self):
        print("Hello from Parent")

class Child(Parent):
    # What goes here?

easy

A. def greet():
print("Hello from Child")

B. def greet(self):
print("Hello from Child")

C. def greet(self, name):
print(f"Hello {name} from Child")

D. def greet(self):
return "Hello from Child"

Solution

1. Step 1: Check method signature for overriding

   The child method must have the same name and parameters as the parent method to override it properly.

2. Step 2: Compare options

   def greet(self): print("Hello from Child") matches the parent's method signature exactly. def greet(): print("Hello from Child") misses 'self', C adds a parameter, and D returns a string instead of printing.

3. Final Answer:

   def greet(self):\n print("Hello from Child") -> Option B

4. Quick Check:

   Same method name and parameters = correct override [OK]

Hint: Match method name and parameters exactly to override [OK]

Common Mistakes:

• Omitting 'self' parameter in method
• Changing method parameters when overriding
• Returning value instead of matching parent's behavior

3.

What will be the output of the following code?

class Animal:
    def sound(self):
        print("Some sound")

class Dog(Animal):
    def sound(self):
        print("Bark")

pet = Dog()
pet.sound()

medium

A. Some sound

B. None

C. Error: Method not found

D. Bark

Solution

1. Step 1: Identify method overriding in Dog class

   Dog class overrides the sound() method from Animal to print "Bark" instead of "Some sound".

2. Step 2: Check which method is called

   When pet.sound() is called, it uses Dog's version, printing "Bark".

3. Final Answer:

   Bark -> Option D

4. Quick Check:

   Child method called = overridden output [OK]

Hint: Child method replaces parent method output [OK]

Common Mistakes:

• Expecting parent method output instead of child's
• Thinking method call causes error
• Confusing print output with return value

4.

Find the error in this code that tries to override a method:

class Vehicle:
    def start(self):
        print("Vehicle started")

class Car(Vehicle):
    def start():
        print("Car started")

c = Car()
c.start()

medium

A. Missing 'self' parameter in Car's start method

B. Car class should not inherit Vehicle

C. Parent method start() is private and cannot be overridden

D. Calling start() without parentheses

Solution

1. Step 1: Check method signature in child class

   Car's start method is missing the 'self' parameter, which is required for instance methods.

2. Step 2: Understand impact of missing 'self'

   Without 'self', Python treats start as a static method, causing a TypeError when called on an instance.

3. Final Answer:

   Missing 'self' parameter in Car's start method -> Option A

4. Quick Check:

   Instance methods need 'self' parameter [OK]

Hint: Always include 'self' as first parameter in instance methods [OK]

Common Mistakes:

• Forgetting 'self' in child method
• Thinking inheritance causes error
• Misunderstanding method call syntax

5.

Given the classes below, what will be the output when c.describe() is called?

class Parent:
    def describe(self):
        print("Parent description")

class Child(Parent):
    def describe(self):
        print("Child description")
        super().describe()

c = Child()
c.describe()

hard

A. Child description

B. Parent description\nChild description

C. Child description\nParent description

D. Error: super() used incorrectly

Solution

1. Step 1: Understand method overriding with super()

   Child's describe() overrides Parent's but calls super().describe() to run parent's method too.

2. Step 2: Trace method calls

   Calling c.describe() prints "Child description" first, then calls Parent's describe() printing "Parent description".

3. Final Answer:

   Child description\nParent description -> Option C

4. Quick Check:

   super() calls parent method after child override [OK]

Hint: super() calls parent method inside child override [OK]

Common Mistakes:

• Expecting only child's print output
• Thinking super() causes error
• Confusing order of prints