assigning values to a dynamically allocated array of structures

This is a discussion on assigning values to a dynamically allocated array of structures within the C Programming forums, part of the General Programming Boards category; Hi, I am trying to dynamically create an array of structures of type page. The page struct looks like this: ...

  1. #1
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    Nov 2008
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    assigning values to a dynamically allocated array of structures

    Hi,
    I am trying to dynamically create an array of structures of type page. The page struct looks like this:

    Code:
     typedef struct
    {
       unsigned short int proc_no;
       unsigned short int page_no;
    } page;
    Then in a function called set_trace, I am using malloc to dynamically create the array. I believe thus far my code is correct, but the next thing I'm trying to do is enter values into this array of structs. This is what my set_trace function looks like.

    Code:
     void set_trace( unsigned short int proc_no, unsigned short int trace[], page *pPter  )
    {
       pPter = malloc( sizeof( page ) * trace_size );
       for( int n = 0; n <= trace_size; n++ )
       {
          pPter.process_number = proc_no;
          pPter.page_number = trace[n];
       }
    }
    For each iteration of the loop, I am trying to assign the proc_no and the value at trace[n] to the nth page in the array. Can someone show me how to do this?

  2. #2
    and the Hat of Guessing tabstop's Avatar
    Join Date
    Nov 2007
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    14,185
    You need to pick a structure first out of your array to assign in to, and then assign it:
    Code:
    pPter[n].process_number = proc_no;
    pPter[n].page_number = trace[n];
    Note that you are trashing memory because your for-loop takes one too many steps.

  3. #3
    Registered User
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    Nov 2008
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    2
    thanks!

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