الوراثة وتعدد الأشكال

class Employee:
    def __init__(self, name, salary):
        self.name = name
        self.salary = salary

    def monthly_pay(self):
        return self.salary

    def describe(self):
        return f"{self.name} earns {self.monthly_pay():,} EGP"


class Manager(Employee):                 # Manager inherits from Employee
    def __init__(self, name, salary, team_size):
        super().__init__(name, salary)   # reuse the parent's __init__
        self.team_size = team_size

    def monthly_pay(self):               # override: change parent behavior
        bonus = self.team_size * 500
        return self.salary + bonus


staff = [Employee("Omar", 12000), Manager("Nour", 25000, team_size=6)]
for person in staff:
    print(person.describe())

class Cash:
    def pay(self, amount):
        return f"Paid {amount} EGP in cash"

class Card:
    def pay(self, amount):
        fee = amount * 0.01
        return f"Paid {amount} EGP by card (+{fee:.0f} fee)"

class MobileWallet:
    def __init__(self, number):
        self.number = number
    def pay(self, amount):
        return f"Paid {amount} EGP from wallet {self.number}"

def checkout(method, total):
    # This function doesn't care WHICH payment type it gets
    print(method.pay(total))

for m in [Cash(), Card(), MobileWallet("010xxxxxxx")]:
    checkout(m, 450)

class Wallet:
    def __init__(self):
        self._balance = 0           # "internal" by convention

    def add(self, amount):
        if amount <= 0:
            raise ValueError("Amount must be positive")
        self._balance += amount

    def get_balance(self):
        return self._balance

w = Wallet()
w.add(200)
print(w.get_balance())