← Computer Programming II

Problem 1: Transport System

You are writing a simple traffic simulation where different forms of transport move using a single common command, regardless of what type of transport they are.

  1. Create a class Car with a method move() that returns the string "Driving on the road.".
  2. Create a class Airplane with a method move() that returns the string "Flying through the sky.".
  3. Create a function start_journey(vehicle) that takes a transport object as an argument, calls its move() method, and prints the result.

Input

car = Car()
plane = Airplane()

start_journey(car)
start_journey(plane)

Expected Output

Driving on the road.
Flying through the sky.
Problem 2: Virtual Orchestra

A music application plays different sounds depending on the instrument selected. You will build a base class and override its method in subclasses.

  1. Create a base class Instrument with an __init__ method that accepts and stores name. Add a method play() that returns the string "Playing the {name}.".
  2. Create a subclass Guitar that inherits from Instrument. Override the play() method to return "Strumming the {name}.".
  3. Create a subclass Drum that inherits from Instrument. Override the play() method to return "Beating the {name}.".
  4. Create a function concert(instruments) that accepts a list of instrument objects and prints the result of calling play() on each one.

Input

instruments = [
    Instrument("flute"),
    Guitar("acoustic guitar"),
    Drum("snare drum")
]

concert(instruments)

Expected Output

Playing the flute.
Strumming the acoustic guitar.
Beating the snare drum.
Problem 3: Fitness Calorie Calculator

A fitness tracking app calculates the total calories burned for different activities. Each workout type has a different calorie burn rate.

  1. Create a class Running with a method calories_burned(minutes) that returns the minutes multiplied by 10.
  2. Create a class Yoga with a method calories_burned(minutes) that returns the minutes multiplied by 4.
  3. Create a function workout_summary(workout, minutes) that accepts a workout object and the duration in minutes. It should print "Burned {amount} calories in {minutes} minutes." by calling the object’s calories_burned method.

Input

run = Running()
yoga = Yoga()

workout_summary(run, 30)
workout_summary(yoga, 45)

Expected Output

Burned 300 calories in 30 minutes.
Burned 180 calories in 45 minutes.
Problem 4: Payment Gateway

An online store supports multiple payment methods. To ensure every new payment method is implemented correctly, you must use an Abstract Base Class (ABC) to enforce a strict contract.

  1. Import ABC and abstractmethod from the abc module.
  2. Create an abstract base class called PaymentProcessor that inherits from ABC.
  3. Define an abstract method process_payment(self, amount).
  4. Create a subclass CreditCardProcessor that inherits from PaymentProcessor. Implement process_payment(amount) so it returns the string "Processing credit card payment of ${amount}".
  5. Create a subclass PayPalProcessor that inherits from PaymentProcessor. Implement process_payment(amount) so it returns the string "Processing PayPal payment of ${amount}".
  6. Write a function checkout(processor, amount) that accepts a payment processor object and an amount, calls its process_payment() method, and prints the result.

Input

cc = CreditCardProcessor()
paypal = PayPalProcessor()

checkout(cc, 150)
checkout(paypal, 45.50)

try:
    p = PaymentProcessor()
except TypeError:
    print("Cannot instantiate abstract class")

Expected Output

Processing credit card payment of $150
Processing PayPal payment of $45.5
Cannot instantiate abstract class
Problem 5: Document Formatter

You are building a system that formats raw text into different output styles. The system should have a common publishing workflow — wrapping formatted text between *** delimiters — but each formatter decides how the text is actually formatted.

Design an abstract base class TextFormatter that enforces subclasses to implement a format_text(self, text) method, while providing a regular publish(self, text) method that wraps the formatted result between *** lines.

Then create two formatters:

  • LoudFormatter — converts text to uppercase.
  • MarkdownFormatter — wraps text in bold markdown syntax (i.e., surrounds text with double asterisks: **text**).

Finally, write a function generate_output(formatter, text) that uses the formatter to publish and print the result.

Input

loud = LoudFormatter()
md = MarkdownFormatter()

generate_output(loud, "Warning")
generate_output(md, "Bold statement")

Expected Output

***
WARNING
***
***
**Bold statement**
***
Problem 6: Rambo's Jungle Survival

Rambo is trapped in the jungle. He must use whatever he finds to fight enemies and survive.

Items in the jungle fall into two categories: weapons (things that can attack a target) and survival gear (things that can be used by a person). Some items — like an explosive arrow — belong to both categories.

Design a system using abstract base classes Weapon (with method attack(self, target)) and SurvivalGear (with method use(self, user)) so that any subclass must implement these methods. Then create an Enemy class with name and health attributes, and three item classes:

  • M60MachineGun — a weapon that deals 40 damage. Its attack method prints "Rambo sprays bullets at {target.name}! (-40 HP)".
  • Medkit — survival gear that heals the user by 50 health points. Its use method prints "Rambo bandages his wounds. (+50 HP)".
  • ExplosiveArrow — an item that is both a weapon (deals 60 damage) and survival gear (heals user by 20 health points). Its attack method prints "Rambo fires an explosive arrow at {target.name}!! BOOM! (-60 HP)". Its use method prints "Rambo uses the arrow powder to start a campfire. (+20 HP)".

The attack method should reduce the target’s health (but not below 0). The use method should increase the user’s health.

Finally, create a Rambo class that starts with health = 100 and an empty inventory. Rambo can pick_up(self, item) items, engage(self, target) enemies (using only items that are weapons), and survive(self) (using only items that are survival gear).

Input

rambo = Rambo()
enemy = Enemy("Sheriff Teasle", 100)

rambo.pick_up(M60MachineGun())
rambo.pick_up(Medkit())
rambo.pick_up(ExplosiveArrow())

rambo.engage(enemy)
print(f"Sheriff Teasle's Health: {enemy.health}")
print("---")
rambo.survive()
print(f"Rambo's Health: {rambo.health}")

Expected Output

Rambo sprays bullets at Sheriff Teasle! (-40 HP)
Rambo fires an explosive arrow at Sheriff Teasle!! BOOM! (-60 HP)
Sheriff Teasle's Health: 0
---
Rambo bandages his wounds. (+50 HP)
Rambo uses the arrow powder to start a campfire. (+20 HP)
Rambo's Health: 170
Problem 7: Space Fleet Command

fleet

You are designing the control software for an intergalactic space fleet. Ships in the fleet have different capabilities: some can move, some can attack, some can heal, and some can do a combination. Your system must handle both official ships that follow strict interfaces and unknown alien technology that doesn’t belong to your class hierarchy but may still have useful abilities.

All ships have name, health, and location attributes. Official ships start with location = "Hangar". The AlienDrone is not part of your class hierarchy, so its location starts as "Unknown".

Define three abstract capability interfaces: Moveable (with warp(self, destination)), Attacker (with fire(self, target)), and Healer (with repair(self, target)).

Then create the following ship classes (each accepts name and health):

  • Fighter — can move and attack. warp updates location and prints "{name} warps to {destination}.". fire deals 30 damage to the target (reduce target.health, but not below 0) and prints "{name} fires at {target.name}! (-30 HP)".
  • MedicalCruiser — can move and heal. warp updates location. repair restores 25 HP to the target and prints "{name} repairs {target.name}. (+25 HP)".
  • DefensePlatform — can only attack (stationary). fire deals 50 damage (not below 0).
  • AlienDrone — can fire (deals 20 damage, not below 0) but is not part of your official class hierarchy.

Create an EnemyShip class with name and health.

Finally, build a Fleet class with add_ship(self, ship) and three command methods:

  • move_fleet(self, destination) — moves all ships that are capable of moving (updating their location); for those that aren’t, print "{ship.name} cannot move!".
  • support(self, target) — has all healers repair the target (increasing its health).
  • all_out_attack(self, target) — fires every ship that has the ability to fire (reducing target.health), including alien ships.

Input

fleet = Fleet()
fighter = Fighter("X-Wing", 100)
medic = MedicalCruiser("Rescue-1", 80)
platform = DefensePlatform("Alpha Station", 200)
drone = AlienDrone("Bzzz-7", 60)

fleet.add_ship(fighter)
fleet.add_ship(medic)
fleet.add_ship(platform)
fleet.add_ship(drone)

fighter.health = 50  # damaged in earlier battle

print("--- Moving Fleet ---")
fleet.move_fleet("Sector 7")
print(f"X-Wing location: {fighter.location}")
print(f"Rescue-1 location: {medic.location}")
print(f"Alpha Station location: {platform.location}")
print(f"Bzzz-7 location: {drone.location}")

print("\n--- Supporting ---")
fleet.support(fighter)
print(f"X-Wing health: {fighter.health}")

print("\n--- All Out Attack ---")
enemy = EnemyShip("Borg Cube", 150)
fleet.all_out_attack(enemy)
print(f"Borg Cube health: {enemy.health}")

Expected Output

--- Moving Fleet ---
X-Wing warps to Sector 7.
Rescue-1 warps to Sector 7.
Alpha Station cannot move!
Bzzz-7 cannot move!
X-Wing location: Sector 7
Rescue-1 location: Sector 7
Alpha Station location: Hangar
Bzzz-7 location: Unknown

--- Supporting ---
Rescue-1 repairs X-Wing. (+25 HP)
X-Wing health: 75

--- All Out Attack ---
X-Wing fires at Borg Cube! (-30 HP)
Alpha Station fires at Borg Cube! (-50 HP)
Bzzz-7 fires at Borg Cube! (-20 HP)
Borg Cube health: 50