for test task

work_with_struct.c

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

#define ALIAS_QUANTITY 10

struct aliasID
{
    char* alias;   /* '\0'-terminated C string */
    int   specific_id;
};

/* How many structures should be pointed to by the array
     */
int GetNumberOfAliases(void)
{
    return ALIAS_QUANTITY;
}

/* Get a pointer to the next structure.  The structure itself
 * will be filled with data.
 * Caller is responsible for the cleanup of the returned structure
 *     and its content. The latter are allocated in
 *     dynamic memory.
 */
struct aliasID * GetNextAlias(void)
{
    struct aliasID *p_ret = (struct aliasID *)malloc(sizeof(struct aliasID));
    if (NULL != p_ret)
    {
        //get data from somewhere and fill up struct
        int i = rand()%1000;    //reduce order of random digit
        char *p_str = (char*)malloc(sizeof(char)*5); //magic number 5: 4 symbols for random digit and 1 for terminate symbol
        itoa(i, p_str, 10); //I know that this function is not part of ANSI C, using it just for sample
        p_ret->specific_id = i;
        p_ret->alias = p_str;
    }
    return p_ret;
}

/* Get a pointer to the array of integers.
 * Caller is responsible for the cleanup of the returned array
 */

int * GetSomeIDs(struct aliasID*** aliasIDs, int* numberOfAliases)
{
    int *p_ret = NULL;
    printf("address after0: %x\n", aliasIDs);
    do
    {
        int i = 0;
        int *p_tmp = NULL;
        *numberOfAliases = GetNumberOfAliases();
        p_tmp = p_ret = (int*)malloc(sizeof(int)* (*numberOfAliases));
        if(NULL == p_ret)
        {
            //error occurs, do something usefull
            break;
        }

        //alocate memory for array of pointers
        *aliasIDs = (struct aliasID *)malloc(sizeof(struct aliasID*) * (*numberOfAliases));
        memset(*aliasIDs, 0, *numberOfAliases);
        printf("address after1: %x\n", aliasIDs);
        if(NULL == aliasIDs)
        {
            //error occurs, do something usefull
            break;
        }

        for (; i < *numberOfAliases; i++)
        {
            struct aliasID *p_alias = GetNextAlias();
            if (NULL != p_alias)
            {
                *p_tmp = p_alias->specific_id;
                (*aliasIDs)[i] = p_alias;
            } else
            {
                *p_tmp = 0; //writes 0 if we can't get new struct
            }
            p_tmp++;
        }
    } while(0);

    return p_ret;
}

void printAllAndCleanUp()
{
    int i = 0;
    struct aliasID **p_aliasID_arr = NULL;
    int numberOfAlias = 0;
    int *p_arr = NULL;
    p_arr = GetSomeIDs(&p_aliasID_arr, &numberOfAlias);
    printf("Content of integer array:\n");
    for (; i < numberOfAlias; i++)
    {
        printf("%d ", *(p_arr+i));
    }

    printf("\nContent of struct array:\n");
    i = 0;
    for (; i < numberOfAlias; i++)
    {
        printf("alias id = %d, alias string = '%s'\n", p_aliasID_arr[i]->specific_id, p_aliasID_arr[i]->alias);
    }

    //clean up
    free(p_arr);
    i = 0;
    for (; i < numberOfAlias; i++)
    {
        free(p_aliasID_arr[i]->alias);
        free(p_aliasID_arr[i]);
    }
    free(p_aliasID_arr);
}

int main(int argc, char ** argv)
{
    printAllAndCleanUp();
    printf("\nAll ok!\n");
    return 0;
}