// Includes.
#include "llist.h"
int main ()
{
char string[20] ;
int found, duplicate ;
NODE *list, *nodeptr ;
int insert( NODE *pList, char *string) ;
int delete( NODE *pList, char *string) ;
NODE *init_list( void) ;
NODE *find( NODE *pList, char *string) ;
void traverse ( NODE *pList) ;
// init LList, dummy nodes
list = init_list();
while( printf ("Enter string (or quit): "),
gets (string),
printf ("%s\n", string),
strcmp ( string, "quit"))
{
duplicate = insert (list, string) ;
if (duplicate)
{
printf ("String in LList already\n") ;
}
}
//
// now print all strings in LList
//
traverse (list) ;
// query user for keys/strings to delete or quit
// lookout for missing keys, warn user.
while( printf("Enter string (or quit): "),
gets (string),
printf ("%s\n", string),
strcmp( string, "quit"))
{
found = delete (list, string) ;
if (!found)
{
printf ("Can't find string in LList node\n") ;
}
else
{
printf ("Deleted node with string %s\n", string) ;
}
}
//
// now print all strings in LList (that survived deletion)
//
traverse (list) ;
// query user for keys/strings to find or quit
// lookout for missing keys, warn user.
while( printf ("Enter string (or quit): "),
gets (string),
printf ("%s\n", string),
strcmp (string, "quit"))
{
nodeptr = find (list, string) ;
if (!nodeptr)
{
printf ("Can't find node w string in LList\n") ;
}
else
{
printf ("Found node with string %s\n", nodeptr->string) ;
}
}
#ifdef TEST2
// populate the LList w strings/keys or quit
// lookout for duplicates, warn user.
// populate the LList w strings/keys or quit
// lookout for duplicates, warn user.
while( printf("Enter string (or quit): "),
gets (string),
strcmp( string, "quit"))
{
printf ("string is %s\n", string) ;
duplicate = insert (list, string) ;
if (duplicate)
{
printf ("String in LList already\n") ;
}
}
//
// now print all strings in LList
//
traverse (list) ;
// query user for keys/strings to find or quit
// lookout for missing keys, warn user.
while( printf("Enter string (or quit): "),
gets (string),
strcmp( string, "quit"))
{
nodeptr = find (list, string) ;
if (!nodeptr)
{
printf ("Can't find node w string in LList node\n") ;
}
else
{
printf ("Found node with string %s\n", nodeptr->string) ;
}
}
#endif
// printf ("main()\n") ;
}
// llist.h
// Include.
#include <stdio.h>
#include <string.h>
#include <stdlib.h> // malloc() and exit()
// Defines.
#define DUMMY_TRAILER '\177'
#define DUPLICATE 1
#define NEW_NODE 0
#define FOUND 1
#define NOT_FOUND 0
// Types.
typedef struct node NODE;
struct node {
char string[20];
NODE *next;
};
// Includes.
#include "llist.h"
// init_list() nodes
// parms (void)
// return ptr to LList (NODE *)
//
NODE *init_list(void)
{
NODE *plist = NULL;
//printf ("init_list(),s\n") ;
if ( (plist = (NODE *) malloc(sizeof(NODE))) == NULL)
{
printf ("Fatal malloc(), init_list()\n"); exit (1);
}
plist->string[0] = '\0' ;
if ( (plist->next = (NODE *) malloc(sizeof(NODE))) == NULL)
{
printf ("Fatal malloc(), init_list()\n"); exit (2);
}
//printf ("plist adrs %x\n", plist) ;
//printf ("plist->next adrs %x\n", plist->next) ;
plist->next->string[0] = DUMMY_TRAILER ;
plist->next->string[1] = '\0' ;
plist->next->next = NULL ;
//printf ("init_list(),e\n") ;
return plist ;
}
// Includes.
#include "llist.h"
// insert() nodes
// parms (ptr to Llist (NODE), ptr to key, (string)
// return value successCode
//
int insert (NODE *plist, char *string)
{
NODE *cur = plist->next ;
NODE *prev= plist ;
NODE *new ;
while ( strcmp(string, cur->string) > 0)
{
prev = cur ;
cur = cur->next ;
}
if ( strcmp(string, cur->string) == 0 )
{
return DUPLICATE ;
}
else
{
if ( ( new = (NODE *)malloc(sizeof(NODE))) == NULL ) {
printf ("Fatal malloc(), insert()\n") ; exit (3) ;
}
strcpy (new->string, string) ;
new->next = cur ;
prev->next = new ;
return NEW_NODE ;
}
}
// Includes.
#include "llist.h"
// delete() a node
// parms (ptr to Llist (NODE), ptr to key, (string)
// return value successCode
//
int delete( NODE *plist, char *string)
{
NODE *cur = plist->next ; //set chasing ptrs, prev, cur
NODE *prev= plist ;
// march thru list, til you've passed "key, string"
while( strcmp( string, cur->string) > 0)
{
prev = cur ;
cur = cur->next ;
}
if( strcmp( string, cur->string) != 0 )
{
return NOT_FOUND ;
}
else
{
prev->next = cur->next ;
free (cur) ;
return FOUND ;
}
}
// Includes.
#include "llist.h"
//
// NODE *find (NODE *pList, char *string)
// params, ptr to LList, NODE *, ptr to key, char *
// return, NODE ptr
// march across LList, printf content of each 'node' (ignore dummies)
NODE *find (NODE *pList, char *string)
{
pList = pList->next ;
while ( strcmp (string, pList->string) >= 0 )
{
if ( strcmp (string, pList->string) == 0 )
{
return pList ;
}
pList = pList->next ;
}
return NULL ;
}
// void traverse (NODE *pList)
// params, ptr to LList, NODE *
// return, none
// march across LList, printf content of each 'node' (ignore dummies)
//
void traverse (NODE *pList)
{
pList = pList->next ;
while (pList->string[0] != DUMMY_TRAILER)
{
printf("%s\n", pList->string) ;
pList = pList->next ;
}
}
