关注点、装饰者、演示者、服务对象、帮助者 - 帮助我理解它们 [关闭]

## 关注点、装饰者、演示者、服务对象、帮助者 - 帮助我理解它们

python
class Circle:
    def __init__(self, radius):
        self.radius = radius
    def area(self):
        return 3.14 * self.radius * self.radius
class Square:
    def __init__(self, side_length):
        self.side_length = side_length
    def area(self):
        return self.side_length * self.side_length
circle = Circle(5)
print("Circle Area:", circle.area())
square = Square(4)
print("Square Area:", square.area())

python
class Coffee:
    def cost(self):
        return 5
class MilkDecorator:
    def __init__(self, coffee):
        self._coffee = coffee
    def cost(self):
        return self._coffee.cost() + 2
coffee = Coffee()
print("Cost of coffee:", coffee.cost())
milk_coffee = MilkDecorator(coffee)
print("Cost of milk coffee:", milk_coffee.cost())

python
class DemoSystem:
    def __init__(self):
        self._state = "Initial State"
    def update_state(self, new_state):
        self._state = new_state
    def show_state(self):
        print("Current State:", self._state)
demo_system = DemoSystem()
demo_system.show_state()
demo_system.update_state("New State")
demo_system.show_state()

python
class CalculatorService:
    def add(self, a, b):
        return a + b
    def subtract(self, a, b):
        return a - b
calculator = CalculatorService()
result_addition = calculator.add(5, 3)
print("Addition Result:", result_addition)
result_subtraction = calculator.subtract(8, 3)
print("Subtraction Result:", result_subtraction)

python
def factorial(n):
    if n == 0 or n == 1:
        return 1
    else:
        return n * factorial(n - 1)
number = 5
print("Factorial of", number, "is", factorial(number))