The switch statement is a clean way to implement multi-way selection (i.e.,selecting from among a number of different execution paths),but it requires a selector that evaluates to an integral value such as int or char.

• switch语句是实现多路选择的一种易行方式(比如从一系列执行路径中挑选一个)。但它要求使用一个选择因子，并且必须是int或char那样的整数值。