Organizing a program into translation units and functions is analogous to structuring a book into a series of chapters ( translation units ) where each chapter consists of several sections ( executable units ) 把程序组织成翻译单元和函数就和把书组织成连续的章节一样（翻译单元） ，尽管每一个章节都是由几个部分（可执行单元）组成。
