a syntax error question..

This is a discussion on a syntax error question.. within the C Programming forums, part of the General Programming Boards category; i got this code and i checked it many times and i cant see why the compiler tells me ?? ...

  1. #1
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    a syntax error question..

    i got this code
    and i checked it many times and i cant see
    why the compiler tells me
    ??

    (57) : error C2143: syntax error : missing ';' before 'type'
    (58) : error C2065: 'i' : undeclared identifier

    Code:
    int main() { 
      int limit; 
      limit=54; 
      
      int i;                                         //line 57
      for(i=1;i<=limit;++i) {            //line58
        print_if_sum_of_abundants(i); 
      }
      return 0;
    }

  2. #2
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    The error is somewhere else in the code (or you have a broken compiler - but I don't think that's the case - I'm pretty sure it's bad code above the main function. I just compiled a copy-n-paste of your code in gcc-mingw.

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  3. #3
    C++ Witch laserlight's Avatar
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    The code looks okay, and this is confirmed when I try to compile. However, I note that the variable i is declared in the middle of a block. This is not allowed in C prior to the 1999 edition of the C standard. However, it is easily fixed with:
    Code:
    int main() { 
      int limit = 54; 
      
      int i;                                         //line 57
      for(i=1;i<=limit;++i) {            //line58
        print_if_sum_of_abundants(i); 
      }
      return 0;
    }
    Now i is declared at the start of the block along with limit.

    EDIT:
    Wait a minute... I'm wrong: the MinGW port of gcc 3.4.5 appears to consider the assignment of 54 to i as an initialisation (and loosely speaking, it is indeed an initialisation), so perhaps I am not clear of the difference between the rules of C and C++. Furthermore, your use of // comments indicates that your code must be C99.
    Last edited by laserlight; 12-08-2008 at 09:25 AM.
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  4. #4
    Technical Lead QuantumPete's Avatar
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    That's because you're using C89, which requires you to declare all variables first, before you use them.
    Hence doing this, will work:
    Code:
    int limit = 54;
    int i;
    QuantumPete
    "No-one else has reported this problem, you're either crazy or a liar" - Dogbert Technical Support
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  5. #5
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    Quote Originally Posted by QuantumPete View Post
    That's because you're using C89, which requires you to declare all variables first, before you use them.
    Hence doing this, will work:
    Code:
    int limit = 54;
    int i;
    QuantumPete
    Good point!

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  6. #6
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by matsp
    Good point!
    Apparently not. Refer to my edit of post #3.
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  7. #7
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    it works thanks

  8. #8
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by transgalactic2
    it works thanks
    As in when you change the definition of limit to be a normal initialisation the error disappears? And at the same time you can use // comments? What compiler are you using and are you compiling in C89 or C99 mode?

    EDIT:
    Oh, I discovered that in my haste I forgot the -pedantic option to gcc, hence gcc did not complain about the declaration in the middle of the block despite -std=c89. Nonetheless, a compiler compiling the code as C89 should have rejected the // comments as syntactically invalid, so it is still strange.
    Last edited by laserlight; 12-08-2008 at 09:34 AM.
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  9. #9
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    i dont know how to check
    if its C89 or C99

    i am using codeblocks 8.02 and vs2005
    to write my program

  10. #10
    Technical Lead QuantumPete's Avatar
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    Quote Originally Posted by laserlight View Post
    Nonetheless, a compiler compiling the code as C89 should have rejected the // comments as syntactically invalid, so it is still strange.
    I think the OP just added the // when forming the question, he probably doesn't have a comment for every line number in his code...

    QuantumPete
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