定义 LSP由Barbara Liskov于1987年提出,一般有两种定义方式: 第一种:If for each object O1 of type S there is an object O2 fo type T such that for all programs P defined in terms of T, the behavior of P is unchanged when
文章正文 2017年1月20日注定是一个会在历史上留下记录的日子,美国第45任总统Donald Trump宣誓就职。他的就职宣誓词非常简短: I do solemnly swear that I will faithfully execute the office of President of the United States, and will to the best of my