【练习】单链表基本操作

/*
* szl_linkedlist.h
*/
#ifndef SZL_LINKEDLIST_H
#define SZL_LINKEDLIST_H

typedef int Element;

typedef struct _tag_node_type Node, ListNode, * PNode, * List, * Position;
void element_assign (Element *, Element *);
void list_init (List * );
List list_append (List * , PNode );
List list_create (List * );
Position list_find (List , Element );
List list_remove (List *, Position );
List list_remove_element (List *, Element );
List list_remove_all_elements (List *, Element );
void list_make_empty (List * );
void list_traverse (List );

#endif

/*
* szl_linkedlist.c
*/
#include "szl_linkedlist.h"
#include <stdlib.h>

static Element new_element ();
static PNode new_node ();

struct _tag_node_type{
Element element;
struct _tag_node_type * link;
};

static Element new_element (){ /* -1 is the end of input. */
Element ret;
scanf("%d", &ret);
return (ret);
}

static PNode new_node (){ /* return NULL when -1 is read */
Element e = new_element();
PNode pnode_ret = NULL;
if(-1 != e){
pnode_ret = (PNode)malloc( sizeof(ListNode));
pnode_ret->link = NULL;
element_assign (&(pnode_ret->element), &e);
}
return pnode_ret;
}

void element_assign (Element * e1, Element * e2){
(*e1) = (*e2);
}

void list_init (List * plist){
(*plist) = NULL;
}

List list_append (List * plist, PNode pnode){
List list = (*plist);
PNode p = list;
if(pnode){
pnode->link = NULL;
if(!list){
(*plist) = pnode;
}
else{
while(p->link){
p = p->link;
}
p->link = pnode;
}
}
return (*plist);
}

List list_create (List * plist){
PNode pnode = new_node();
while(pnode){
list_append (plist, pnode);
pnode = new_node();
}
return (*plist);
}

Position list_find (List list, Element value){
Position position = list;
while(position){
if(position->element == value){
break;
}
position = position->link;
}
return position;
}

List list_remove_element (List * plist, Element e){
Position position = list_find (*plist, e);
return (list_remove (plist, position));
}

List list_remove_all_elements (List * plist, Element e){
Position position = list_find (*plist, e);
while (position){
list_remove (plist, position);
position = list_find (*plist, e);
}
return (*plist);
}

List list_remove (List * plist, Position position){
Position pnode_p, pnode_q;
if (!(*plist)){
return (*plist);
}
else{
pnode_p = (*plist);
pnode_q = pnode_p;
while(pnode_p){
if (pnode_p == position){
break;
}
pnode_q = pnode_p;
pnode_p = pnode_p->link;
}
if(pnode_p){
if(pnode_p == pnode_q){
(*plist) = (*plist)->link;
free (pnode_p);
pnode_p = pnode_q = NULL;
}
else{
pnode_q->link = pnode_p->link;
free (pnode_p);
pnode_p = NULL;
}
}
return (*plist);
}
}

void list_make_empty ( List * plist){
PNode pnode_p, pnode_q;
pnode_p = (*plist);
while (NULL != pnode_p){
pnode_q = pnode_p;
pnode_p = pnode_p->link;
free (pnode_q);
}
(*plist) = NULL;
}

void list_traverse (List list){
Position p = list;
while(p){
printf("%d\n", p->element);
p = p->link;
}
}

/*
* szl_linkedlist_test.c
*/
#include <stdio.h>
#include <stdlib.h>
#include "szl_linkedlist.h"

int main(int argc, char * argv[]){
List l;
list_init (&l);
list_create (&l);
list_traverse (l);

list_remove_all_elements(&l,2);
list_traverse (l);
list_make_empty (&l);

return 0;
}