Question

I have this code for now:

pacient sortClients(int n, pacient *lista, int print)
{
    pacient aux[50];  

    for(i=0;i<n;i++)
    *(aux+i)=*(lista+i);

    //some modifications performed on aux

    return *aux;
}

void sortAndShowByAge(int n, pacient *lista)
{
   pacient aux[50];
   *aux=sortClients(n,lista,0);

}

The last function is where I get in trouble. If aux has only one record then it works ok, if there are more than two, it shows some weird characters. In the first function I iterated over lista and saved every record to aux. Is there a way to assign the aux from sortClients to aux in shortAndShowByAge directly and not iterate? I can’t iterate over sortClients.

Answer 1

Your code simply returns a single element, rather than the entire array. It can’t legally return the array as written, since it’s a local variable.

You need to either allocate new memory dynamically, or sort in-place.

The former, which is most like what you have already, would go like this:

pacient * sortClients(int n, const pacient *lista, int print)
{
    pacient *aux;

    if((aux = malloc(n * sizeof *aux)) != NULL)
    {
      memcpy(aux, lista, n * sizeof *aux);
      /*some modifications performed on aux */
    }
    return aux;
}

This returns a pointer to the sorted/processed array, which you must call free() on when you’re done with, in order not to leak memory.

I alao corrected the return type, and use memcpy() instead of a manual loop to copy the input values. The input array is marked as const too, since it’s read-only for the function.