lists, memory, pointers?

hi every1,

im kind of new to programming and i have a question about lists. i found a pretty neatly done code from this site
The C Programming Language
Ron Wein's C Examples: list.c
for doubly linked lists.

in his code ron defines an element structure which will be used to append data into the doubly linked list, it contains a struct element *prev, struct element *next, and data .

in his append function here is what he writes

Code:

/* ------------------------------------------------------------------------

 * Function: list_append

 */

void list_append (List *p_list, double x)

{

  Element *p_elem;

  /* Sanity check: */

  if (p_list == NULL)
    exit(-1);

  /* Allocate a new Element object and set its fields. */
  p_elem = (Element *) malloc (sizeof(Element));

  p_elem->value = x;

  p_elem->p_prev = NULL;

  p_elem->p_next = NULL;

  /* Set the element as the new list tail. */

  if (p_list->p_tail != NULL)

  {

    /* The new element should be placed after the current list tail. */
    p_list->p_tail->p_next = p_elem;

    p_elem->p_prev = p_list->p_tail;

    /* Set the new element as the new list tail. */
    p_list->p_tail = p_elem;

  }
  else
  {

    /* The list is empty - the new element should be both its head and
       its tail. */

    p_list->p_head = p_elem;

    p_list->p_tail = p_elem;

  }
  /* Increment the list size. */
  p_list->size++;

  return;

}

here is my question.

in the line where it says

p_elem = (Element *) malloc (sizeof(Element));

whats the purpose for declaring a pointer to struct Element, and afterwards allocating the struct size.

i am aware of the need to allocate the memory for then data can be written to it, but what i dont understand is the need for the (Element *). what will this do to p_elem, how is it relevant for the list?
is the p_elem pointer already set by the

Element *p_elem;

Actually, you don't need it. malloc() returns a void * which can be assigned to any pointer.

Old time C used to require that the types matched exactly, so that was a kludge to make the old compilers happy. But like the previous poster said, its completely unnecessary using any modern compiler.

thx for the answers guys. i can go on programming without bugging my concience for a while again