continue statement

This is a discussion on continue statement within the C++ Programming forums, part of the General Programming Boards category; I rarely ever see continue used in a program. There's not many times when it'd be needed, but even in ...

  1. #1
    myNegReal
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    continue statement

    I rarely ever see continue used in a program. There's not many times when it'd be needed, but even in certain times other ways are usually used. Is it just not common, or does it have some drawbacks or slowdowns?

  2. #2
    Registered User major_small's Avatar
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    I use it whenever needed... some people say it fits in with goto in the fact that it makes for spaghetti code, but I tend to disagree...
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  3. #3
    myNegReal
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    Ah, cool, yeah I think continue is a handy little statement, but I was thinking maybe it had some problems that kept many people from using it.

  4. #4
    Registered User major_small's Avatar
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    nah... I have yet to hear any good arguments as to why not to use it (but if anybody has any, I'm more than willing to listen)
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  5. #5
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    I rarely ever see continue used in a program. There's not many times when it'd be needed, but even in certain times other ways are usually used. Is it just not common, or does it have some drawbacks or slowdowns?
    It's unstructured like goto, which is considered by some to be bad. As far as slow downs, the only case I can think of is if the compiler has trouple detecting the loop. The unstructured jump to the top might affect how the compiler detects inner and outer loops.

    You probably don't see it often because the best cases to use it are either in empty loops, where you'd normally code
    Code:
    while(condition)
          ;
    using continue, you'd code
    Code:
    while(condition)
           continue;
    or in short cut offs like
    Code:
    while(condition) {
          if (cond2)
                continue;
    
          // followed by long section of code
    
    }

  6. #6
    myNegReal
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    Yeah I was gonna use it for a cutoff like you exampled, but it's for a game, so I wanted to make sure it wouldn't be slow or anything.

  7. #7
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    I use it a lot in short cutoffs as okinrus showed. I prefer to use continue than to add a new nesting level.

  8. #8
    Confused Magos's Avatar
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    It has its uses, instead of making a large "if" or a deeply nested "if":
    Code:
    for(int i = 0; i < NrOfObjects; i++)
    {
      if(ObjectTooBig(i)) continue;
      if(ObjectTooSmall(i)) continue;
      if(ObjectTooExpensive(i)) continue;
      if(ObjectTooUgly(i)) continue;
      if(ObjectTooFat(i)) continue;
      if(ObjectTooHilarious(i)) continue;
      if(ObjectTooDark(i)) continue;
      if(ObjectTooLight(i)) continue;
      if(ObjectTooWeird(i)) continue;
      if(ObjectTooNormal(i)) continue;
    
      UseObject(i);
      break;
    }
    Clean, clear, readable!
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  9. #9
    and the hat of wrongness Salem's Avatar
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    Code:
    for ( i = 0 ; i < numPosts ; i++ ) {
      if ( posterUsesVoidMain(i) ) continue;
      if ( posterUsesFflushStdin(i) ) continue;
      if ( posterUsesGetsForInput(i) ) continue;
      if ( posterCodeFormattingSucks(i) ) continue;
      if ( posterQuotesSchildt(i) ) continue;
      if ( !posterReadFAQ(i) ) continue;
      if ( posterCrossPosting(i) ) continue;
      if ( posterBumpingThread(i) ) continue;
      if ( posterUrgencyLevel(i) > 0 ) continue;
      if ( !(posterStatedCompiler(i) &&
             posterStatedOperatingSystem(i) ) ) continue;
      AnswerPost(i);
    }
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  10. #10
    Just Lurking Dave_Sinkula's Avatar
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    If I may, here is an example from C99:
    EXAMPLE 1 It is sometimes convenient to jump into the middle of a complicated set of statements. The following outline presents one possible approach to a problem based on these three assumptions:
    1. The general initialization code accesses objects only visible to the current function.
    2. The general initialization code is too large to warrant duplication.
    3. The code to determine the next operation is at the head of the loop. (To allow it to be reached by continue statements, for example.)
      Code:
      /* ... */
      goto first_time;
      for (;;) {
            // determine next operation
            /* ... */
            if (need to reinitialize) {
                  // reinitialize-only code
                  /* ... */
            first_time:
                  // general initialization code
                  /* ... */
                  continue;
            }
            // handle other operations
            /* ... */
      }
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

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