以电子版发布此书的目的是提高国内CAD开发者的普遍水平，让入门者更快地能够编 写代码，让初级程序员更快达到中高级程序员的水平。为国内CAD开发整体水平的提高， 我们愿意尽一份微薄之力。-Electronic release the book' s purpose is to improve the general level of domestic CAD developers, beginners to quickly be able to write code, so that