Python class and object problems

Problem 1: Creating a Book Class

Problem Statement:

Design a Book class in Python that has the following attributes and methods:

Attributes:

• title (string): the title of the book.

• author (string): the author of the book.

• price (float): the price of the book.

• quantity (int): the quantity of the book in stock.

Methods:

• __init__(self, title, author, price, quantity): Initializes a new book object with the given title, author, price, and quantity.

• get_price(self): Returns the price of the book.

• set_price(self, new_price): Sets a new price for the book.

• get_quantity(self): Returns the quantity of the book in stock.

• set_quantity(self, new_quantity): Sets a new quantity for the book in stock.

• sell(self, number_sold): Decreases the quantity of books in stock by number_sold. If number_sold is more than the available quantity, print "Not enough stock".

• restock(self, number_added): Increases the quantity of books in stock by number_added.

Example Usage:

# Create a new book instance
my_book = Book(title="1984", author="George Orwell", price=29.99, quantity=100)

# Get and set price
print(my_book.get_price())  # Output: 29.99
my_book.set_price(24.99)

# Sell and restock
my_book.sell(5)
print(my_book.get_quantity())  # Output: 95
my_book.restock(10)
print(my_book.get_quantity())  # Output: 105

Problem 2: Implementing a Circle Class

Problem Statement:

Create a Circle class in Python that represents a circle with the following specifications:

Attributes:

• radius (float): The radius of the circle.

Methods:

• __init__(self, radius): Initializes a new circle object with the given radius.

• area(self): Returns the area of the circle.

• circumference(self): Returns the circumference of the circle.

Constants:

• PI (float): A class-level constant representing the value of π (pi).

Example Usage:

# Create a new circle instance
my_circle = Circle(radius=5)

# Get area and circumference
print(my_circle.area())  # Output: 78.54 (approximately)
print(my_circle.circumference())  # Output: 31.42 (approximately)

Problem 3: Building a Bank Account Class

Problem Statement:

Design a BankAccount class in Python with the following attributes and methods:

Attributes:

• account_number (string): The account number.

• balance (float): The balance in the account.

Methods:

• __init__(self, account_number, initial_balance): Initializes a new bank account object with the given account number and an initial balance.

• deposit(self, amount): Deposits the given amount into the account. If the amount is negative, print "Invalid amount".

• withdraw(self, amount): Withdraws the given amount from the account. If the amount is greater than the balance, print "Insufficient funds".

• get_balance(self): Returns the current balance of the account.

Example Usage:

# Create a new bank account instance
my_account = BankAccount(account_number="12345678", initial_balance=1000)

# Deposit and withdraw
my_account.deposit(500)
my_account.withdraw(200)
print(my_account.get_balance())  # Output: 1300

Problem 4: Creating a Vehicle Class

Problem Statement:

Develop a Vehicle class in Python with the following details:

Attributes:

• make (string): The make of the vehicle (e.g., Toyota, Ford).

• model (string): The model of the vehicle (e.g., Camry, Mustang).

• year (int): The year the vehicle was manufactured.

• mileage (int): The current mileage of the vehicle.

Methods:

• __init__(self, make, model, year, mileage): Initializes a new vehicle object with the specified make, model, year, and mileage.

• drive(self, miles): Increments the mileage of the vehicle by the specified number of miles.

• get_info(self): Returns a string containing the make, model, year, and mileage of the vehicle.

Example Usage:

# Create a new vehicle instance
my_vehicle = Vehicle(make="Toyota", model="Camry", year=2020, mileage=25000)

# Drive the vehicle
my_vehicle.drive(200)

# Get vehicle info
print(my_vehicle.get_info())  # Output: "Toyota Camry, 2020, 25200 miles"

Problem 5: Implementing a Student Class

Problem Statement:

Create a Student class in Python with the following attributes and methods:

Attributes:

• name (string): The name of the student.

• grades (list of floats): The list of grades for the student.

Methods:

• __init__(self, name): Initializes a new student object with the given name and an empty grade list.

• add_grade(self, grade): Adds a new grade to the student's grade list.

• get_average(self): Returns the average of the student's grades.

Example Usage:

# Create a new student instance
student = Student(name="Alice")

# Add grades and get average
student.add_grade(90)
student.add_grade(95)
student.add_grade(85)
print(student.get_average())  # Output: 90.0

Problem 6: Building a Rectangle Class

Problem Statement:

Design a Rectangle class in Python to represent a rectangle with the following characteristics:

Attributes:

• length (float): The length of the rectangle.

• width (float): The width of the rectangle.

Methods:

• __init__(self, length, width): Initializes a new rectangle object with the specified length and width.

• area(self): Returns the area of the rectangle.

• perimeter(self): Returns the perimeter of the rectangle.

Example Usage:

# Create a new rectangle instance
rectangle = Rectangle(length=5, width=3)

# Calculate area and perimeter
print(rectangle.area())      # Output: 15
print(rectangle.perimeter()) # Output: 16

Problem 7: Creating a Temperature Converter Class

Problem Statement:

Implement a Temperature class in Python that can convert temperatures between Fahrenheit and Celsius with the following specifics:

Attributes:

• temperature (float): The temperature value.

• unit (string): The unit of the temperature ('C' for Celsius, 'F' for Fahrenheit).

Methods:

• __init__(self, temperature, unit): Initializes a new temperature object with the specified temperature and unit.

• convert_to_fahrenheit(self): Converts the temperature to Fahrenheit and updates the unit.

• convert_to_celsius(self): Converts the temperature to Celsius and updates the unit.

Example Usage:

# Create a new temperature instance in Celsius
temp = Temperature(temperature=0, unit='C')

# Convert to Fahrenheit
temp.convert_to_fahrenheit()
print(temp.temperature)  # Output: 32.0

# Convert back to Celsius
temp.convert_to_celsius()
print(temp.temperature)  # Output: 0.0