用python写一个自动贩卖机有限状态机

好的，下面是一个简单的自动贩卖机有限状态机的 Python 代码：

class VendingMachine:
    def __init__(self):
        self.balance = 0
        self.items = {
            "cola": {"price": 1.5, "quantity": 10},
            "chips": {"price": 1, "quantity": 5},
            "candy": {"price": 0.5, "quantity": 2}
        }
        self.current_state = self.idle_state

    def idle_state(self):
        print("Welcome to the vending machine!")
        print("Please insert coins or select an item.")
        print(f"Current balance: {self.balance} dollars.\n")
        action = input("Enter coin amount or item name: ")
        if action in self.items:
            self.current_state = self.item_selected_state
            self.selected_item = action
        else:
            self.balance += float(action)

    def item_selected_state(self):
        item = self.items[self.selected_item]
        if item["quantity"] == 0:
            print(f"Sorry, {self.selected_item} is sold out.")
            self.current_state = self.idle_state
        elif self.balance < item["price"]:
            print("Insufficient funds. Please insert more coins.")
            self.current_state = self.idle_state
        else:
            self.balance -= item["price"]
            item["quantity"] -= 1
            print(f"Thank you for purchasing {self.selected_item}!")
            print(f"Your change is {self.balance} dollars.")
            self.current_state = self.idle_state

    def run(self):
        while True:
            self.current_state()

这个自动贩卖机有三种商品（cola, chips, candy），并且可以接受硬币。在初始状态下，它会提示用户插入硬币或选择商品。如果用户选择了商品，它会进入“item_selected_state”，检查商品是否有库存，用户是否有足够的余额，并且发出购买成功的消息。购买成功后，它会返回“idle_state”并等待下一个操作。如果商品没有库存或余额不足，它会返回“idle_state”并提示用户。你可以调用 `VendingMachine().run()` 来运行这个自动贩卖机。