6. 什么是泛型 generic?
• Generic programming is a style of computer
programming in which algorithms are written in terms of
types to-be-specified-later that are then instantiated
when needed for specific types provided as parameters.
• 泛型是程序设计语言的一种风格或范式。泛型允许程序员
在实现算法逻辑时,延迟声明具体的数据类型,即实例化
时才把具体类似作为参数传递。