你是否曾在检查代码时碰到一条在你看来多余的注释?在代码中使用注释的目的是提升代码的可读性,以让那些非原始代码开发者能更好地理解它们。
我甄别出5类让我不胜其扰的注释及5类生成它们的程序员。我希望读过本篇之后,你不会与他们一样坠入同一条河流。作为一项挑战,你不妨把写这5类注释的程序员与5类程序员[英文]作一下匹配。
1. 骄傲型程序员
- public class Program
- {
- static void Main(string[] args)
- {
- string message = "Hello World!"; // 07/24/2010 Bob
- Console.WriteLine(message); // 07/24/2010 Bob
- message = "I am so proud of this code!"; // 07/24/2010 Bob
- Console.WriteLine(message); // 07/24/2010 Bob
- }
- }
这类程序员对其代码自视甚高,以至于他觉得有必要在每行代码后都要签上自己的大名。应用版本控制系统(VCS)是能知道谁修改了代码,但是乍看之下责任人也不会如此打眼。
2. 过时型程序员
- public class Program
- {
- static void Main(string[] args)
- {
- /* This block of code is no longer needed
- * because we found out that Y2K was a hoax
- * and our systems did not roll over to 1/1/1900 */
- //DateTime today = DateTime.Today;
- //if (today == new DateTime(1900 1 1))
- //{
- // today = today.AddYears(100);
- // string message = "The date has been fixed for Y2K.";
- // Console.WriteLine(message);
- //}
- }
- }
如果一段代码不再使用了(也就是过时了),请删除它——勿要让你的工作代码被数行冗余的注释弄得七零八乱。而且,你任何时候需要复制这段删除的代码,都可以使用版本控制系统,这样你便能从以前版本中恢复出它来。
3. 显然型程序员
- public class Program
- {
- static void Main(string[] args)
- {
- /* This is a for loop that prints the
- * words "I Rule!" to the console screen
- * 1 million times each on its own line. It
- * accomplishes this by starting at 0 and
- * incrementing by 1. If the value of the
- * counter equals 1 million the for loop
- * stops executing.*/
- for (int i = 0; i < 1000000; i++)
- {
- Console.WriteLine("I Rule!");
- }
- }
- }
我们都知道编程的基本工作逻辑——这可不是什么“编程入门”!你无需浪费时间解释显而易见的程序工作原理,虽然我们很高兴看到你愿意解释代码的功能——但这不过是画蛇添足。
4. 传记型程序员
- public class Program
- {
- static void Main(string[] args)
- {
- /* I discussed with Jim from Sales over coffee
- * at the Starbucks on main street one day and he
- * told me that Sales Reps receive commission
- * based upon the following structure.
- * Friday: 25%
- * Wednesday: 15%
- * All Other Days: 5%
- * Did I mention that I ordered the Caramel Latte with
- * a double shot of Espresso?
- */
- double price = 5.00;
- double commissionRate;
- double commission;
- if (DateTime.Today.DayOfWeek == DayOfWeek.Friday)
- {
- commissionRate = .25;
- }
- else if (DateTime.Today.DayOfWeek == DayOfWeek.Wednesday)
- {
- commissionRate = .15;
- }
- else
- {
- commissionRate = .05;
- }
- commission = price * commissionRate;
- }
- }
如果你非得在代码中提到某些必需的东西,也别提到人名。Jim from Sales(译注:销售人员Jim)也许离开这家公司了,那些阅读代码的程序员极可能根本就不知道他是谁,更甭提注释里那些毫无干系的事情。
5. “总有一天”型程序员
- public class Program
- {
- static void Main(string[] args)
- {
- //TODO: I need to fix this someday – 07/24/1995 Bob
- /* I know this error message is hard coded and
- * I am relying on a Contains function but
- * someday I will make this code print a
- * meaningful error message and exit gracefully.
- * I just don’t have the time right now.
- */
- string message = "An error has occurred";
- if(message.Contains("error"))
- {
- throw new Exception(message);
- }
- }
- }
这类注释在某种程度上说是前面几种类型的大杂烩。TODO注释在项目初始开发阶段用处不小,但是如果几年后出现在产品代码中——那就会带来麻烦。如果有什么需要修补的,趁现在动手,而不要推迟到以后去做。
如果你不幸是生成这些类型注释的人,或者你想学习注释用法的***实践,我推荐你阅读Steve McConnell写的Code Complete(《代码大全》)。这是一本我建议程序员必读的书籍,OSC地址 http://my.oschina.net/justjavac/blog/66624。
你是否在自己的代码中看到了其它类型多余或扰人的注释?请不吝分享。