画一个取款机的UML类图

好的，以下是一个简单的取款机的UML类图：

+----------------------------------+
|           ATM                    |
+----------------------------------+
| - balance: float                 |
| - cardInserted: boolean          |
| - cashDispenser: CashDispenser   |
| - keypad: Keypad                 |
| - screen: Screen                 |
+----------------------------------+
| + insertCard(): void             |
| + ejectCard(): void              |
| + enterPin(): void               |
| + withdrawCash(amount: float): void |
+----------------------------------+

+----------------------------------+
|         CashDispenser            |
+----------------------------------+
| - cashCount: int                 |
+----------------------------------+
| + dispenseCash(amount: float): boolean |
+----------------------------------+

+----------------------------------+
|             Keypad               |
+----------------------------------+
|                                  |
+----------------------------------+
| + getInput(): string             |
+----------------------------------+

+----------------------------------+
|             Screen               |
+----------------------------------+
|                                  |
+----------------------------------+
| + display(message: string): void |
+----------------------------------+

以上类图中，ATM 类包含了所有与取款机相关的操作，如插卡、退卡、输入密码、取款等。CashDispenser 类负责处理现金的分配，Keypad 类处理输入，Screen 类处理输出。所有类之间的交互都通过 ATM 类来进行。