list-functions.c - Funktionen member.

Lektion 9 - slide 22 : 29 Program 3

/* Is el member of list as a data element? 
   Comparisons are done by reference equality */
int member(void *el, cons_cell *list){
  if (list == NULL)
    return 0;
  else if (head(list) == el)
    return 1;
  else
    return member(el, tail(list));
}