#include <stdio.h>
#include <string.h>
#define NL 20
typedef struct tree
{
char tree_name [NL];
struct tree* next;
}tree;
void
print_trees(tree* head)
{
if (head == NULL) printf("\n"); //simple case: empty list
else {
printf("%s\n", head -> tree_name); //general case: first element
print_trees(head -> next); //general case: rest of the list
}
}
int
main (void)
{
/* declaring variables to hold tree nodes */
tree tree1, tree2, tree3, tree4;
/* declaring the starting and traveling pointers */
tree *p, *start;
/* putting tree names into each node */
strcpy (tree1.tree_name, "Maple");
strcpy (tree2.tree_name, "Fir");
strcpy (tree3.tree_name, "Pine");
strcpy (tree4.tree_name, "Oak");
/* setting the start of the list at tree1 */
start = &tree1;
/* linking the other trees together */
tree1.next = &tree2;
tree2.next = &tree3;
tree3.next = &tree4;
/* sets tree4 as the last node of the list */
tree4.next = NULL;
/* printing out the list by traveling though it with a loop */
p = start;
while (p != NULL)
{
printf ("%s\n", p -> tree_name);
p = p -> next;
}
printf ("\n");
/* printing out the list by using a recursive function */
print_trees (start);
return (0);
}
