Relationships (association, aggregation, composition) in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an association relationship between two classes.

LLD

class Teacher:
    def __init__(self, name):
        self.name = name

class Student:
    def __init__(self, name, teacher):
        self.name = name
        self.teacher = [1]

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

Ateacher

Bname

CStudent

Dself

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'name' instead of 'teacher' causes the student to store a string, not the teacher object.

Using 'self' or 'Student' is incorrect as they do not refer to the teacher instance.

The student holds a reference to the teacher object, representing an association.

2fill in blank

medium

Complete the code to show aggregation where a Library has many Books.

LLD

class Book:
    def __init__(self, title):
        self.title = title

class Library:
    def __init__(self):
        self.books = []

    def add_book(self, book):
        self.books.[1](book)

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

Aremove

Bappend

Cclear

Dpop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'remove' or 'pop' deletes items instead of adding.

Using 'clear' empties the list, which is not intended.

Aggregation means the library holds references to book objects. We add books to the list using append.

3fill in blank

hard

Fix the error in the composition example where a Car has an Engine.

LLD

class Engine:
    def __init__(self, power):
        self.power = power

class Car:
    def __init__(self, power):
        self.engine = [1](power)

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

Apower

Bengine

CEngine

DCar

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'engine' or 'power' as a function causes errors.

Using 'Car' tries to create a Car inside Car, which is incorrect.

In composition, the Car creates and owns the Engine instance. We must call the Engine class to create it.

4fill in blank

hard

Fill both blanks to complete the aggregation example where a Team has multiple Players.

LLD

class Player:
    def __init__(self, name):
        self.name = name

class Team:
    def __init__(self):
        self.players = []

    def add_player(self, player):
        self.players.[1](player)

    def remove_player(self, player):
        self.players.[2](player)

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

Aappend

Bpop

Cremove

Dclear

Attempts:

3 left

💡 Hint

Common Mistakes

Using pop to remove by value causes errors.

Using clear removes all players, not just one.

To add a player, use append. To remove a specific player, use remove.

5fill in blank

hard

Fill all three blanks to complete the composition example where a House has Rooms with names and sizes.

LLD

class Room:
    def __init__(self, name, size):
        self.name = [1]
        self.size = [2]

class House:
    def __init__(self):
        self.rooms = []

    def add_room(self, name, size):
        room = [3](name, size)
        self.rooms.append(room)

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

Aname

Bsize

CRoom

Dself

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up parameter names or using 'self' incorrectly.

Not calling the Room class to create a new object.

The Room constructor assigns name and size to its attributes. The House creates Room instances to compose rooms.