realloc realloc realloc

This is a discussion on realloc realloc realloc within the C++ Programming forums, part of the General Programming Boards category; Perhaps this will make the code I posted a little while ago easier to understand: PHP Code: /* if srchitem is found in the array, its position is  returned, however many times it occurs (the positions  are to be written to 'foundpositions' array).  ...

  1. #1
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    realloc realloc realloc

    Perhaps this will make the code I posted a little while ago easier to understand:

    PHP Code:
    /* if srchitem is found in the array, its position is 
    returned, however many times it occurs (the positions 
    are to be written to 'foundpositions' array). 
    size is the size of the array, fsize is the size of 
    the positions array. */ 

    int *seqsearch (double *aradouble srchitemint size) { 
       
    int *foundpositions
       
    int fsize 0// size of foundpositions 
       
    for ( int x=0x<sizex++) 
          if (*(
    ara+x) == srchitem) { 
          
    foundpositions = (int *) realloc (foundpositions, ( (fsize+1)*sizeof(int) )); 
          
    // allocate memory to foundpositions array 
          // as elements matching srchitem are found. 
          
    fsize ++; 
          *(
    foundpositions+x) = x
       } 
       return (
    foundpositions); 


  2. #2
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    Try initialising your foundpositions to NULL.

  3. #3
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    Doesn't realloc initialize it to null the first time anyway?

  4. #4
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    Thumbs up

    No, that actually worked, thanks!

  5. #5
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    >Doesn't realloc initialize it to null the first time anyway?

    realloc doesn't have to move the allocated block. If it initialised the pointer to NULL everytime then it may be destroying your previously allocated data. How does it know that it's the first time?

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