Question about pointers #2

This is a discussion on Question about pointers #2 within the C++ Programming forums, part of the General Programming Boards category; "The disadvantages far outweigh any advantages that hungarian notation has." What disadvantages are you referring to? It seems like a ...

  1. #16
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    "The disadvantages far outweigh any advantages that hungarian notation has."

    What disadvantages are you referring to? It seems like a good idea to me, it allows someone to identify what type a variable is just by looking at the name.

  2. #17
    mustang benny bennyandthejets's Avatar
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    I also think it is a good idea. How could there possibly be any disadvantages to adding a prefix?
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  3. #18
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    ><snip godawful hungarian notation>

    I was scared to say anything when I saw that suggestion for a descriptive name, but that's close to what I was thinking. It's bad enough to see it in a Windows program, but I sure don't want to see it in a non-Windows program.

    It's one of those style issues: some love it, some hate it! I wonder if we've had a Poll on it here. I know I've seen threads discussing it in the past.
    Last edited by swoopy; 06-19-2004 at 10:18 PM.

  4. #19
    mustang benny bennyandthejets's Avatar
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    but I sure don't want to see it in a non-Windows program.
    GIVE A REASON WHY NOT
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  5. #20
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    From my very preliminary research on Hungarian Notation it seems that there is no set standard, every individual or organization has its own version, but if there was one official standard for variable prefixing that EVERYONE used, well, I cannot see any downsides to it.

  6. #21
    mustang benny bennyandthejets's Avatar
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    I can't see a downside to prefixing a variable name with it's type. It's certainly made things easier for me. I'd really like to see some disadvantages.
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  7. #22
    Code Goddess Prelude's Avatar
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    >I'd really like to see some disadvantages.
    Okay.

    1) It hurts abstraction to encode the type in everything. Let's say I have a C program that needs to be ported to C++. One of the variables is pszUserName. Well, we know that the variable contains a name, so it's probably a string, and the hungarian notation tells us that it's a pointer to a C-style string. All is well, right? No, not really. Abstraction says that we shouldn't care about the type as long as it's used according to the correct interface. There's no point in prefixing psz.

    2) Okay, on to the port. Because any wise programmer will try to use std::string instead of C-style strings, the definition of pszUserName is changed to
    Code:
    std::string pszUserName;
    At this point the programmer must make a decision. The type has changed, so she can change every occurance of pszUserName to some house standard for std::string, or leave the name unchanged and incorrect. Global changes are relatively easy these days, but there are snags for sweeping changes. Was hungarian notation really worth it if it requires so much effort to maintain?

    A more realistic example is const. Say you use a pointer for a while and then later decide that it would be safer to make it const. I do this all of the time because it's convenient during development. Well, using hungarian notation you would have to change the name of every occurance of that pointer to reflect its const-ness. Can you remember to do that without fail? I can't.

    3) Hungarian notation keeps track of types, but in a typed language such as C++ it's redundant. A well written C++ program will either have a declaration of the variable close at hand, or hidden by proper object-oriented techniques. With the former it's trivial to check the type and with the latter the type shouldn't matter (not to mention that hungarian notation has no prefix for such types). If a well structured program makes hungarian notation redundant, why cling to it?

    4) One should be able to pronounce a variable name. This makes sense as programmers aren't left in a void to work their magic, they communicate with other programmers, often face to face. Hungarian notation makes this more difficult in a good many languages besides English.

    5) Sheer obscurity. Even if you know hungarian notation, many find that reading code that uses it is harder than reading code that doesn't. You obscure the purpose by embedding information that shouldn't be necessary.

    6) Inaccuracy. Hungarian notation is simply a way of commenting code. A lot of people recognize that comments aren't always kept up-to-date and are inaccurate. This is because they aren't policed by the compiler for correctness. The same goes with hungarian notation. When reading code that uses it, how can you be sure that it's correct?

    7) By writing code that uses hungarian notation, you make the job of a maintenance programmer harder. But you also make your job harder (also for little gain, see above) by forcing yourself to type awkward prefixes for every name. This has a twofold effect: First, you spend extra time embedding types that could be used more effectively elsewhere and second, you focus on the type of a variable so much that it's possible to forget its use and mess something up. In this, and a few other points, hungarian notation breeds bugs.

    This list is off the top of my head and far from exhaustive, BTW.
    My best code is written with the delete key.

  8. #23
    S Sang-drax's Avatar
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    Argument from the microsoft site in favor of hungarian notation:

    Speed of the decision—we cannot spend too much time pondering the name of a single quantity, nor is there time for typing and editing extremely long variable names.
    Hehe.
    Last edited by Sang-drax : Tomorrow at 02:21 AM. Reason: Time travelling

  9. #24
    vae victus! skorman00's Avatar
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    Kudos Prelude! I've always wanted to bring my ideas into concise statements, but it always came down to "well...um...if you...when something like this happens....It's just fricken annoying!"

    It's great for windows stuff where I would most likely write out things like handle in a variable name for clearness anyway. And having a tag infront of global and member variables is convenient...sometimes =)

  10. #25
    and the hat of int overfl Salem's Avatar
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    > Speed of the decision—we cannot spend too much time pondering the name of a single quantity
    If you spent any reasonable time actually designing what you wanted before writing it, the names become obvious. Perhaps the "patch-a-week" brigade would do well to learn this lesson.

    Also, code is read much more often than it is written. If it's done well, it gets written exactly once. That code should be first and foremost readable is paramount to me. Anything which compromises readability (that would be HN), then its a "bad thing" in my book.

    Just to add to Prelude's excellent comment
    Why not just get rid of the cryptographic nature of hungarian and say what you mean
    const char *pszName;
    would become
    const char *const_char_pointer_Name;
    It is at this point you realise that the type declaration is essentially repeated information. So why not just say
    const_char_pointer_Name;
    and let the compiler figure out what you meant. Unfortunately, this language is no longer 'C'. If you want to write a compiler for this new language, that's up to you.

    > 2) Okay, on to the port
    Yes, because the 'L' in LPSTR is now completely meaningless in a 32 bit context.
    But no you can't get rid of it, it's just some meme virus that will refuse to go away for many many years to come. New generations of programmers will wonder what it means and various folklore tales will emerge to explain it.

    A couple of more reasons
    1. Primitive types are first class, everything else is second class.
    So pointers, ints, chars etc all get their own special letter. But what about all your structs, classes and typedefs?
    Do you go with something meaningless like say 'C' for all classes (that's really informative)
    Or do you smash your way through the abstraction and reveal the underlying types.

    2. No-one can seem to agree on all the letter combinations, even within a local organisation. Common letters get reused for all sorts of purposes. Depending on context (which you can only really get by going and looking at the actual declaration - oops, we wanted to avoid that), 's' could mean say 'signed' 'struct' 'string'

    Having read Simonyi's original description, I came to the conclusion that the whole idea was akin to training wheels on a child's bycicle. Fine when you're learning not to fall over, but utterly useless once you're experienced enough - they simply get in the way!!!
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  11. #26
    mustang benny bennyandthejets's Avatar
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    Ok, I see where you're coming from. However, in my experience those disadvantages have not had any effect on my programming. It takes little to no effort to put in hungarian notation in the way that I do, and I firmly believe that it increases the readability of my code. I think it takes a bit of pedantacy to really care.
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  12. #27
    mustang benny bennyandthejets's Avatar
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    To whoever gave me the bad reputation for my capitalized post earlier, I was annoyed that Prelude and other people were making bold statements without providing any examples or proof.
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  13. #28
    Code Goddess Prelude's Avatar
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    >It takes little to no effort to put in hungarian notation in the way that I do, and I firmly believe that it increases the readability of my code.
    We weren't trying to force you not to use hungarian notation, just explaining why many people disapprove of it. If it works for you then so be it, but it never hurts to hear the other side's arguments so that you can better defend your own position. Rest assured that in a serious code review, you'll probably be called on your naming scheme and have to give a detailed account of why you use it.
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  14. #29
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    >To whoever gave me the bad reputation for my capitalized post earlier

    Now why didn't I think of that?

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