﻿<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/"><channel><title>C++博客-蜂蜜-随笔分类-EFFECTIVE C++</title><link>http://www.cppblog.com/inbeing/category/12597.html</link><description>酷造</description><language>zh-cn</language><lastBuildDate>Sun, 20 Dec 2009 16:34:56 GMT</lastBuildDate><pubDate>Sun, 20 Dec 2009 16:34:56 GMT</pubDate><ttl>60</ttl><item><title>条款2：尽量以CONST，ENUM，INLINE替换#DEFINE</title><link>http://www.cppblog.com/inbeing/archive/2009/12/21/103601.html</link><dc:creator>蜜蜂</dc:creator><author>蜜蜂</author><pubDate>Sun, 20 Dec 2009 16:18:00 GMT</pubDate><guid>http://www.cppblog.com/inbeing/archive/2009/12/21/103601.html</guid><wfw:comment>http://www.cppblog.com/inbeing/comments/103601.html</wfw:comment><comments>http://www.cppblog.com/inbeing/archive/2009/12/21/103601.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.cppblog.com/inbeing/comments/commentRss/103601.html</wfw:commentRss><trackback:ping>http://www.cppblog.com/inbeing/services/trackbacks/103601.html</trackback:ping><description><![CDATA[<span  style="font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; "><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">类中定义常量：static const int numturns = 5;</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">这是声明式而非定义式。若不需取它们的地址，无须提供定义式。定义式如下：</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">const int GamePlayer::NumTurns;</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; "><br></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; "><br></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">一个class需要常量值，定义如下：</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">enum{NumTurns = 5};</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">int scores[NumTurns];</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; "><br></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; "><br></p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">关于&#8220;形似函数的宏，最好改用inline函数替换#defines&#8221;</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">但，经验证明。宏的速度要比用inline的方法快。</p><p style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; ">在一些对速度要求非常严格的项目中，这个方面还是要有所取舍的。</p></span>
<img src ="http://www.cppblog.com/inbeing/aggbug/103601.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.cppblog.com/inbeing/" target="_blank">蜜蜂</a> 2009-12-21 00:18 <a href="http://www.cppblog.com/inbeing/archive/2009/12/21/103601.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item></channel></rss>