"can I do this" question

[Arcand]

ok so under the advisement of my tutor/teacher I am writing my first pseudo code document for a project decently large for my history and my question is this, is it possible to pass a pointer to an array that stores the whole array, not just one part of it?

an example would be

char my_array[<sub_1_max>][<sub_2_max>];
char *myptr = my_array[<sub_1>][<sub_2>]

the above code would point to the specific position defined by <sub_1> and <sub_2>, but how would I call a pointer to just my_array and actively access its members based on what part I want the code to access next?

thanks, I hope this makes sense, if it doesnt ill write up some small program to illustrate.

[rjjj]

Create a pointer to the beginning of the array :

#include <stdio.h>


int main(void)
{
    char x[] = "String";
    char *y = NULL;
    y = &x[0];
    puts(y);
    getchar();
    return 0;
}

I hope that I have helped .

[Arcand]

lmao. that's so idiotically simple I cant believe I didnt think of it. Thanks

[ledow]

Agreed. Just pass a pointer to the array. They can then calculate the offset they need to access any part of the array. If they want to fiddle with it non-destructively, they can make their own copy of it from the given pointer using memcpy (and so that you haven't sent tons of array data between functions, which actually wouldn't work on a lot of old or embedded compilers / architectures with small "stacks", but just a single pointer).

You might also want to have the function pass the size of the array too, purely because at some point you'll realise that you'll need it in the function and have to put it in anyway (it's a very common thing to pass an array pointer and its size to a function, and how do you know how much to memcpy or whether you're accessing out of bounds if you aren't told the SIZE of the array too?).

Personally, I'd be worried about those functions, over time, accessing the array out of bounds, so I'd probably create some sort of wrapper functions they can use to provide access, and discourage them accessing the array directly e.g.:

void function(char *array)
{
    char first_element = get_first_element(array);
    int size = get_size_of_array(array);
    char nth_element = get_nth_element(array, n);
}

etc.

and from there, depending on how much I trust the calling functions and what I'm doing with the array, I might even go to abstract out the concept of the array to a particular structure (e.g. struct Array, with appropriate functions that can act on it etc. and then just pass a struct Array to your function). But that's probably a step too far for a simple array in a program you've wrote yourself, if I'm honest.