考虑这样一个水果篮，里面之多可以有10个苹果（Apple）和香蕉（Banana），它们都派生自一个叫做水果（Fruit）的基类使用集合接口IEnummerable和IEnumerator实现装入水果的过程和遍历水果-Consider a fruit basket, which can have as many as 10 Apple (Apple) and banana (Banana), they are derived from a fruit called (Fruit) of the b