/*
**  Written by David Gerdes  US Army Construction Engineering Research Lab
**  	April 1992
**  Copyright 1992 USA-CERL   All rights reserved.
**
*/

/*
**  takes 1st command line argument and stuffs each letter of it into
**   a linked list.  then prints it back out to stdout.
**  If a second argument is specified, the first argument is put in the
**   list backwards.
*/
#include <stdio.h>
#include <grass/linkm.h>

struct link {
    char let;
    struct link *next;
};

int 
main (int argc, char *argv[])
{
    register int i;
    VOID_T *head;
    struct link List, *tmp, *p;
    int rev = 0;

    if (argc < 2)
	fprintf (stderr, "Usage: %s str [rev]\n", argv[0]), exit (1);

    if (argc > 2)
	rev = 1;


    List.next = NULL;
    List.let = ' ';
    

    head = (VOID_T *) link_init (sizeof (struct link));

    for (i = 0 ; argv[1][i] ; i++)
    {
	tmp = (struct link *) link_new (head);
	tmp->let = argv[1][i];
	if (rev)
	    add_link_rev (&List, tmp);
	else
	    add_link (&List, tmp);
    }

    dumplist (&List);

    p = List.next;
    while (p->next != NULL)
    {
	tmp = p->next;
	link_dispose (head, p);
	p = tmp;
    }

    link_cleanup (head);

    exit (0);
}

int 
add_link_rev (struct link *List, struct link *link)
{
    struct link *p;

    p = List->next;
    List->next = link;
    link->next = p;
}

int 
add_link (struct link *List, struct link *link)
{
    struct link *p;

    p = List;
    while (p->next != NULL)
	p = p->next;
    p->next = link;
    link->next = NULL;
}

int 
dumplist (struct link *List)
{
    struct link *p;

    p = List->next;
    while (p != NULL)
    {
	putchar (p->let);
	p = p->next;
    }
    putchar ('\n');
}
