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

typedef struct num_list {
	int element; // number
	struct num_list *next; // pointer to next cell
} Cell; // one cell of the list

typedef Cell *List; // pointer to a list


/* Inserts number at the beginning of list L. L points to
 * the first element of the list - a dummy cell storing the
 * number of cells in the list.
 */
void insert_list(int number, List L);

/* Searches for occurance of number in list L. Returns a pointer
 * to thecell just before the cell containing number, if it exists.
 * Returns NULL otherwise.
 */
List search_list(int number, List L);

/* Deletes the cell containing number in the list L, if it exists.
 * Returns -1 otherwise.
 */
int delete_list(int number, List L);

/* Prints the elements of list L */
void print_list(List L);