strtok() and strcpy

This is a discussion on strtok() and strcpy within the C Programming forums, part of the General Programming Boards category; hi, im just learning c and im trying to copy the token to a 2 dimension char array but the ...

  1. #1
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    strtok() and strcpy

    hi, im just learning c and im trying to copy the token to a 2 dimension char array but the array( eq1[][] ) just gets filled with nulls. i cant figure out what im doing wrong...


    Code:
    void tokenize(void){
       extern char equation[];
       extern eq1[];
       int i = 0;
       char *token;
    
       token = strtok( equation, " ");
       while ( token != NULL ){
          printf( "token is %s\n", token);
          strcpy(eq1[i], token);
          token = strtok( NULL, " ")
          printf("eq is %s\n", eq1[i]);
          ++i;
       }
    }
    if anyone could help me out id really appreciate it

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    Presumably you have eq1 defined in your function correctly? Right now it's not a two-d array for you to fill.

  3. #3
    spurious conceit MK27's Avatar
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    I pretty sure right now it is not even something that will pass a compiler:

    Code:
    extern eq1[];
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

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    its just a typo, its actually declared like:

    extern char eq1[][];

    the strtok seems to work, the printf's work but wheni display eq1 i get (null)

  5. #5
    spurious conceit MK27's Avatar
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    Quote Originally Posted by grimlark View Post
    its just a typo, its actually declared like:
    So how many more typos do we have to deal with before we get to the real thing? Cut and paste the actual code you are using, or stop trying to waste other people's time.
    C programming resources:
    GNU C Function and Macro Index -- glibc reference manual
    The C Book -- nice online learner guide
    Current ISO draft standard
    CCAN -- new CPAN like open source library repository
    3 (different) GNU debugger tutorials: #1 -- #2 -- #3
    cpwiki -- our wiki on sourceforge

  6. #6
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    its the only typo, and it is the actual code im using. i just cant figure out why im getting (null) in eq1 instead of token

  7. #7
    and the Hat of Guessing tabstop's Avatar
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    Quote Originally Posted by grimlark View Post
    its the only typo, and it is the actual code im using. i just cant figure out why im getting (null) in eq1 instead of token
    Like we all didn't see the missing semicolon either.

  8. #8
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    Quote Originally Posted by grimlark View Post
    its just a typo, its actually declared like:

    extern char eq1[][];

    the strtok seems to work, the printf's work but wheni display eq1 i get (null)
    Surely you need to specify at least the second of those array sizes, so that the compiler can determine where to store the strings.

    What is your eq1 defined as? My guess would be that you are mismatching the definition and the declaration, if the first suggestion I made isn't the cause of the problem.

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    Mats
    Compilers can produce warnings - make the compiler programmers happy: Use them!
    Please don't PM me for help - and no, I don't do help over instant messengers.

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