说明： 再附上一个软件开发生命周期引言的一个PPT文档，相信结合上面推荐的文档，大家会对软件开发生命周期有个感性的认识了 (addresses a software development life cycle introduction of a PPT file, I believe that the combination of the above recommendation document, we will software development life cycle has a perceptual understanding of)
