dynamic memory allocation char array

This is a discussion on dynamic memory allocation char array within the C Programming forums, part of the General Programming Boards category; Hi, Im trying to dynamically allocated the number of elements to my char array. Whats the best way to do ...

  1. #1
    Waxy-Dock
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    dynamic memory allocation char array

    Hi,

    Im trying to dynamically allocated the number of elements to my char array. Whats the best way to do this.. maybe something like this?

    int sizeofarray = 10;

    char *myarray = malloc(sizeof(char)*sizeofarray);

    then i need to access the array normally like myarray[9] = 'g';

    am i on the right track?

  2. #2
    Woof, woof! zacs7's Avatar
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    yep, but remember that sizeof(char) == 1, so its pretty redundant, for example:

    Code:
    char * myarray;
    const unsigned short int myarray_size = 10;
    
    if((myarray = malloc(myarray_size)) == NULL)
    {
        perror("malloc failed");
        exit(1);
    }
    /* do as you will with myarray, remember to stay in bounds tho! */

  3. #3
    and the hat of wrongness Salem's Avatar
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    Unless you adopt the idiomatic
    p = malloc ( num * sizeof *p );

    which works for all types, and saves you having to think about exceptions to rules who's only side effect is to save a bit of typing.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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