malloc_array_in_function_and_then_access_array_from_outside.c

/*

    malloc_array_in_function_and_then_access_array_from_outside.c

https://stackoverflow.com/questions/8437791/c-malloc-array-in-function-and-then-access-array-from-outside


    You can find all my C programs at Dragan Milicev's pastebin:

    https://pastebin.com/u/dmilicev

*/

#include<stdio.h>
#include <stdlib.h>

// creates a memory location for array arr[n] of n integers
// and fills it with ordinal numbers
void create_array(int **arr, int arr_size) {
    *arr = malloc(sizeof(int) * arr_size);

    if (arr == NULL) {  // Check if the memory has been successfully allocated by malloc
        printf("\n Memory not allocated. \n");
        return;
    }

    // optionally, we can fill the array of integers with ordinal numbers
    for(int i=0; i<arr_size; i++)
        (*arr)[i] = i+1;
}

int main() {
    int *arr, arr_size=10;

// create a memory location for array arr[n] of n integers and fills it with ordinal numbers
    create_array(&arr, arr_size);

    printf("\n\n");

    for (int i=0; i<arr_size; i++)
        printf("%4d", arr[i]);  // arr[i] is the same as *(arr + i)
                                // so arr[0] is the same as *arr
    printf("\n\n");

    free(arr);                  // keep it clean

    return 0;
}