The Weird and The Wonderful

   

The Weird and The Wonderful forum is a place to post Coding Horrors, Worst Practices, and the occasional flash of brilliance.

We all come across code that simply boggles the mind. Lazy kludges, embarrassing mistakes, horrid workarounds and developers just not quite getting it. And then somedays we come across - or write - the truly sublime.

Post your Best, your worst, and your most interesting. But please - no programming questions . This forum is purely for amusement and discussions on code snippets. All actual programming questions will be removed.

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Re: What this 'null' check doing here... David C. Thompson10-Jul-13 3:05 David C. Thompson 10-Jul-13 3:05  Probably code that has been edited and then not refactored. No real wtf here, ey? Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 19:39 Mohammed Hameed 10-Jul-13 19:39  But that's not the case I have verified the previous versions from source control... Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... David C. Thompson10-Jul-13 20:51 David C. Thompson 10-Jul-13 20:51  lol. Then its probably just a brain fart, or late night coding session Re: What this 'null' check doing here... Mark Starr10-Jul-13 4:25 Mark Starr 10-Jul-13 4:25  Guess I don't know c# well enough, but I didn't this you could use any comparison operator against NULL. it's probably bad practice to even if the language allows it. Re: What this 'null' check doing here... KP Lee10-Jul-13 20:19 KP Lee 10-Jul-13 20:19  Mark Starr wrote: I didn't this you could use any comparison operator against NULL You're mixing up SQL with C# as well as "this" vs "think". SQL isn't case sensitive and comparison operators won't work with null, NULL, or NuLl where all versions of the null keyword are valid. In C#, NULL is nonsense unless you've declared an object name NULL and the language is designed to make comparisons (==, !=) with null Re: What this 'null' check doing here... Mark Starr11-Jul-13 5:18 Mark Starr 11-Jul-13 5:18  Yup: I don't know C# well enough. Agreed. And, I didn't capitalize the 'i' at the beginning of the next sentence. Re: What this 'null' check doing here... KP Lee15-Jul-13 20:32 KP Lee 15-Jul-13 20:32  This thread started with: C# List<Employee> employees = new List<Employee>(); if (employees != null){ employees = GetEmployees(); There are layers of things wrong with just this bit of code. "employees = new ..." created a new object, it is impossible for "if (employees != null)" to return false. (Others have said memory critical operations might have problems, but that can't happen because if it did happen, the behavior of C# is to throw an error. In which case, "if" would never execute. THEN it executes "employees = GetEmployees()" which threw the "=..." part of "employees = new ..." into the trash. NOW employees may or may not be null and no if checking if it is null or not is done, it just assumes that since it wasn't null it still isn't null. It is incredible how much bad code can be compressed into so little space, so it is worth posting in the weird and wonderful. The following code has exactly the same amount of effective error checking as the first bit of code: C# List<Employee> employees = GetEmployees(); Sorry, I wasn't trying to bash you about your knowledge. (I was teasing you about your mistyping, thinking you wrote it while tired and made an easy mistake to make when you are tired.) The SQL part of what I said was just trying to teach you a little bit of the difference between the two languages. Everyone is ignorant in some things in their lives. Nothing wrong with that. There is something wrong with wanting to be ignorant and I didn't think that was happening with you. Re: What this 'null' check doing here... Mark Starr16-Jul-13 5:20 Mark Starr 16-Jul-13 5:20  Not a prob, I was in fact, just starting the day, and clearly had too little coffee in my system to type, much less proof. We had just been playing around with javascript to see what happens when you don't declare a variable versus when you declare it and don't assign a value - how it affects checking for undefined, not-undefined, null, etc. And, Yes, I typically write a lot more in T-SQL, but I also use VB, VB.NET, et al in my daily work - hence my disclaimer about not writing a lot of C#. I'm always careful when checking for nulls, so when I see comparison operator my hair stands up a bit. Initially, to me, the code looked as though someone had somehow had a bad experience populating the list from using the "new List<employee>();" call, and so put in a safety-catch (if you will) to try again if necessary. Or, perhaps, the second part was already there, and someone later came along and added the first line... I'm sure they though it was right at the time. Who knows! Thanks for the note KP. Cheers and happy coding, Mark Re: What this 'null' check doing here... GrumpyPants10-Jul-13 5:33 GrumpyPants 10-Jul-13 5:33  Check your version control. It's possible declaration and/or the assignment at declaration was added later. If an earlier version of the method had the List<employee> passed as a parameter, then the test for non-null would make sense. Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 19:35 Mohammed Hameed 10-Jul-13 19:35  Quote: It's possible declaration and/or the assignment at declaration was added later. Ok but in the case if it is added later also, the guy should have removed the null check as it is not applicable now. Anyhow that wasn't the case, I checked the source control Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... RafagaX10-Jul-13 5:43 RafagaX 10-Jul-13 5:43  I bet the person who wrote this comes from a C/C++ background, there, you have to check for null every time or you may blow out something... CEO at: - Rafaga Systems - Para Facturas - Modern Components for the moment... Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 19:43 Mohammed Hameed 10-Jul-13 19:43  Correct. *** You're superb,,, What a guess!!! *** Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... Michael Losinski10-Jul-13 5:59 Michael Losinski 10-Jul-13 5:59  The only thing that I can think of is technically new doesn't guarantee that the variable initialization will take place. In programming languages like c++ it could return null. This could happen if the memory was so fragmented that the allocation failed. However, instead of returning null in C# I believe it throws a out of memory exception. I have only seen this done in system critical embedded systems. Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 19:45 Mohammed Hameed 10-Jul-13 19:45  Thanks Michael. That was a excellent explanation. Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... KP Lee10-Jul-13 21:01 KP Lee 10-Jul-13 21:01  Michael Losinski wrote: The only thing that I can think of is technically new doesn't guarantee that the variable initialization will take place. Who cares? If the "if" check returns true, the result of calling the routine could make it null. If it's mission critical, initialize it by calling the function and then throw it when the function sets it to null. (Which it doesn't seem to check for, when that is a very possible result of calling the function.) If you are so constrained by memory the new would fail, it'd fail in the function too, thereby throwing an error the code doesn't check for(catch). Re: What this 'null' check doing here... Michael Losinski11-Jul-13 3:40 Michael Losinski 11-Jul-13 3:40  Yes you could the code down to one line of code. You could catch the exception somewhere else, so I suppose the question could then become what do you do in a mission critical system when outofmemory exception or an allocation fails, therefore allowing you to gracefully shutdown. First thing that comes to mind is if the current thread is not mission critical you can kill that can free up some memory. Second, you could have a fail-safe that would allow you to kill all non-mission critical threads thus freeing memory. With the right permissions you could also kill the other applications. I've never implemented one but you could also have a "memory para-shoot" that at the start of the program allocates a chunk of memory and frees it when needed. I suppose allot of it depend on the system and requirements. Re: What this 'null' check doing here... Nilesh Shahane10-Jul-13 8:07 Nilesh Shahane 10-Jul-13 8:07  He is just double checking. Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 19:47 Mohammed Hameed 10-Jul-13 19:47  The same thing I told him when I saw this first time. Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... MainFrameMan_ALIVE_AND_WELL$$10-Jul-13 10:03 MainFrameMan_ALIVE_AND_WELL$$ 10-Jul-13 10:03  Looks like a newbie whose prof in 101 programming hammered down checking objects before using them. This would be sensible if it were a thousand lines down in the code, but, if it is null where is the property/method to new it up? Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 19:48 Mohammed Hameed 10-Jul-13 19:48  Well, he is 4 yrs exp..... Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... KP Lee10-Jul-13 21:13 KP Lee 10-Jul-13 21:13  Mohammed Hameed wrote: Well, he is 4 yrs exp.... So, he IS inexperienced! (I started coding in '74. Late start, '05 on C#.) Re: What this 'null' check doing here... Mohammed Hameed10-Jul-13 21:15 Mohammed Hameed 10-Jul-13 21:15  Ohh, is that? Previous -> Read "CLR via C#" by Jeffrey Ritcher. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. Re: What this 'null' check doing here... DarkChuky CR12-Jul-13 12:56 DarkChuky CR 12-Jul-13 12:56  it could make sense if it was a code update... let say it was like: XML List<Employee> employees = GetEmployessFromSucursal(sucursalID); if (employees != null){ employees = GetEmployees();//Get employes from other source } then for some reason the code was updated or copy&paste... there is also a proba that the IF used to have some other parameter and an ELSE... so again code that was not finally updated to the best final form. Re: What this 'null' check doing here... Mohammed Hameed14-Jul-13 19:46 Mohammed Hameed 14-Jul-13 19:46  Thanks. My Reading-o-Meter Previous -> Read "CLR via C#" by Jeffrey Richter. Current -> Exploring WCF thru Apress' "Pro WCF" by Chris Peiris and Dennis Mulder. Next -> Need to read "The Art of Computer Programming" by Donald E. Knuth. My blog - My recent article Re: What this 'null' check doing here... Chad3F13-Jul-13 19:17 Chad3F 13-Jul-13 19:17  Now a smart compiler should probably want about this. Something like when comparing signed and unsigned int's in C and it warns that the statement is always true (or false) due to conversion rules. Seems like maybe (I know.. "maybe?!?!") a programmer that didn't know what they're doing. That you have to first "create" the list, so you can "fill it in" with the GetEmployees() values or something. Along the same lines as novice programmers that create and assign a local number (or string) variable with a constant value because the function was prototyped with that data type, rather than pass the same constant number inline to the call. Could be worse.. I've seen this in [employed to write] software: C++ #define ZERO 0 #define ONE 1 #define TWO 2

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