need help with structures

This is a discussion on need help with structures within the C Programming forums, part of the General Programming Boards category; Code: struct vix { char *pname; int day; int month; int year; int hour; int min; } ; struct vix ...

  1. #1
    ~viaxd() viaxd's Avatar
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    need help with structures

    Code:
    struct vix {
         char *pname;
         int day;
         int month;
         int year;
         int hour;
         int min;
     } ;
     
    struct vix *pvix;
    
    pvix = malloc ( siz * sizeof  *pvix );
    
    for ( j = 0; j < siz; j++ )
    fscanf(fp,"%d.%d.%d %d:%d %s",&(pvix+j)->day,&(pvix+j)->month,&(pvix+j)->year,
    &(pvix+j)->hour,&(pvix+j)->min,(pvix+j)->pname);
    
    for ( i = 0; i < siz; i++ )
       printf("%d %d %s\n",i,(pvix+i)->day,(pvix+i)->pname);
    
    free(pvix);
    Why does this give me an error at run time?...

  2. #2
    Just Lurking Dave_Sinkula's Avatar
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    >Why does this give me an error at run time?...

    Where is (pvix+j)->pname pointing? (You need to allocate memory for it.)
    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.*

  3. #3
    ~viaxd() viaxd's Avatar
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    >You need to allocate memory for it.
    how would i do that?

    btw the file contains something like

    01.01.2003 00:00 test
    11.11.2002 10:30 test2
    etc...

  4. #4
    and the hat of int overfl Salem's Avatar
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    > how would i do that?
    Well the easy way is to make your structure member an array
    char pname[20];

    > &(pvix+j)->day
    Too complicated
    Try
    &pvix[j].day
    Just like what you would do if it were a regular array
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
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  5. #5
    ~viaxd() viaxd's Avatar
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    ok, now there's no more errors but the output is strange :
    0 0 ?
    1 0 ?
    2 0 ?
    etc...
    i use this to print :
    Code:
    for ( i = 0; i < siz; i++ )
         printf("%d %d %s\n",i,pvix[j].day,pvix[j].pname);

  6. #6
    Just Lurking Dave_Sinkula's Avatar
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    Code:
    for ( i = 0; i < siz; i++ )
         printf("%d %d %s\n",i,pvix[j].day,pvix[j].pname);
    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.*

  7. #7
    ~viaxd() viaxd's Avatar
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    haha i guess i'm blind , thanks Dave

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