Ревізії 策略模式在購物車計價中的應用

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1 file changed, 39 insertions

pricing_strategy_normal_discount_shopping_cart.py(файл створено)

		@@ -0,0 +1,39 @@
1	+	from abc import ABC, abstractmethod
2	+
3	+	# 策略介面
4	+	class PricingStrategy(ABC):
5	+	@abstractmethod
6	+	def calculate_price(self, price):
7	+	pass
8	+
9	+	# 具體策略類
10	+	class NormalStrategy(PricingStrategy):
11	+	def calculate_price(self, price):
12	+	return price
13	+
14	+	class DiscountStrategy(PricingStrategy):
15	+	def __init__(self, discount_rate):
16	+	self.discount_rate = discount_rate
17	+
18	+	def calculate_price(self, price):
19	+	return price * (1 - self.discount_rate)
20	+
21	+	# 上下文類
22	+	class ShoppingCart:
23	+	def __init__(self, pricing_strategy):
24	+	self.pricing_strategy = pricing_strategy
25	+
26	+	def set_pricing_strategy(self, pricing_strategy):
27	+	self.pricing_strategy = pricing_strategy
28	+
29	+	def checkout(self, items):
30	+	total_price = sum(items)
31	+	return self.pricing_strategy.calculate_price(total_price)
32	+
33	+	# 使用範例
34	+	cart = ShoppingCart(NormalStrategy())
35	+	items = [100, 200, 300]
36	+	print("Total price with normal strategy:", cart.checkout(items)) # Output: Total price with normal strategy: 600
37	+
38	+	cart.set_pricing_strategy(DiscountStrategy(0.2))
39	+	print("Total price with discount strategy:", cart.checkout(items)) # Output: Total price with discount strategy: 480

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