Data structures and algorithms: Implementation and encapsulation of unidirectional linked lists

An overview of the

One-way linked list can be divided into one-way headed list and single-line headless list. In this paper, C language is used to implement and encapsulate one-way headed list.

implementation

list_head h file

#ifndef _LIST_H_
#define _LIST_H_
typedef int datatype;
#define SUCC
#define MALLOC_FAIL 1
#define NOHEADNODE 2
#define INDEXFAIL 3
#define LIST_EMPTY 4
#define LIST_NOEMPTY 5
#define FAIL  10
typedef struct List_Node 
{
 datatype data;
 struct List_Node* pNext;
}list;
list*list_create();
int list_insert_at(list* pHead, int i, datatype* pData);
int list_order_insert(list* pHead, datatype* pData);
int list_delete_at(list* pHead, int index);
int list_delete(list* pHead, datatype* pData);
int list_isempty(list* pHead);
void list_display(list* pHead);
void list_destory(list* pHead);
#endif // !_LIST_H_

list_head c file

/********************************************************
Copyright (C), 2016-2017,
FileName: list
Author: woniu201
Description: Unidirectional header linked list use 
********************************************************/
#include <stdio.h>
#include "list_head.h"
/************************************
@ Brief:  Create the watch header 
@ Author: woniu201 
@ Return:   
************************************/
list* list_create()
{
 list* pNode = (list *)malloc(sizeof(list));
 memset(pNode, 0, sizeof(list));
 if (pNode == NULL)
 {
 return MALLOC_FAIL;
 }
 pNode->pNext = NULL;
 return pNode;
}
/************************************
@ Brief:  Insert nodes by position 
@ Author: woniu201
@ Return:
************************************/
int list_insert_at(list* pHead, int i, datatype* pData)
{
 int j = 0;
 if (pHead == NULL)
 {
 return NOHEADNODE;
 }
 list* pNode = pHead;
 if (i<0)
 {
 return INDEXFAIL;
 }
 while (j< i && pNode !=NULL)
 {
 pNode = pNode->pNext;
 j++;
 }
 if (pNode == NULL)
 {
 return INDEXFAIL;
 }
 else
 {
 list* newNode = (list*)malloc(sizeof(list));
 if (newNode ==NULL)
 {
  return MALLOC_FAIL;
 }
 memset(newNode, 0, sizeof(list));
 newNode->data = *pData;
 pNode->pNext = newNode;
 }
 return SUCC;
}
/************************************
@ Brief:  The nodes are inserted in order 
@ Author: woniu201
@ Return:
************************************/
int list_order_insert(list* pHead, datatype* pData)
{
 if (pHead == NULL)
 {
 return NOHEADNODE;
 }
 list* pNewNode = (list*)malloc(sizeof(list));
 if (pNewNode == NULL)
 {
 return MALLOC_FAIL;
 }
 memset(pNewNode, 0, sizeof(list));
 pNewNode->data = *pData;
 list* pNode = pHead;
 if (pNode->pNext == NULL)
 {
 pNode->pNext = pNewNode;
 return SUCC;
 }
 while (pNode->pNext != NULL && pNode->pNext->data < *pData)
 {
 pNode = pNode->pNext;
 }
  if (pNode->pNext)
  {
 pNewNode->pNext = pNode->pNext;
 pNode->pNext = pNewNode;
  }
 else
 {
 pNode->pNext = pNewNode;
 }
 return SUCC;
}
/************************************
@ Brief:  Delete nodes by location 
@ Author: woniu201
@ Return:
************************************/
int list_delete_at(list* pHead, int index)
{
 int j = 0;
 if (pHead == NULL)
 {
 return NOHEADNODE;
 }
 if (index < 0)
 {
 return INDEXFAIL;
 }
 list* pCur = pHead;
 list* pNode = pHead;
 while (pCur->pNext)
 {
 pNode = pCur;
 pCur = pCur->pNext;
 if (index == j)
 {
  break;
 }
 j++;
 }
 if (j< index)
 {
 printf(" This node does not exist \n");
 return INDEXFAIL;
 }
 else
 {
 if (pCur->pNext == NULL)
 {
  pNode->pNext = NULL;
 }
 else
 {
  pNode->pNext = pCur->pNext;
 }
 free(pCur);
 pCur = NULL;
 }
 return SUCC;
}
/************************************
@ Brief:  Delete nodes by value 
@ Author: woniu201
@ Return:
************************************/
int list_delete(list* pHead, datatype* pData)
{
 if (pHead == NULL)
 {
 return NOHEADNODE;
 }
 list* pCur = pHead;
 list* pNode = pHead;
 int bFind = 0;
 while (pCur->pNext)
 {
 pNode = pCur;
 pCur = pCur->pNext;
 if (pCur->data == *pData)
 {
  bFind = 1;
  break;
 }
 }
 if (!bFind)
 {
 printf(" This node does not exist \n");
 return INDEXFAIL;
 }
 else
 {
 if (pCur->pNext == NULL)
 {
  pNode->pNext = NULL;
 }
 else
 {
  pNode->pNext = pCur->pNext;
 }
 free(pCur);
 pCur = NULL;
 }
 return SUCC;
}
/************************************
@ Brief:  Determine if the list is empty 
@ Author: woniu201
@ Return:
************************************/
int list_isempty(list* pHead)
{
 if (pHead->pNext == NULL)
 {
 return LIST_EMPTY;
 }
 else
 {
 return LIST_NOEMPTY;
 }
}
/************************************
@ Brief:  Walk through the printed list 
@ Author: woniu201
@ Return:
************************************/
void list_display(list* pHead)
{
 if (list_isempty(pHead) == LIST_EMPTY)
 {
 printf(" The list is empty \n");
 return FAIL;
 }
 list* pNode = pHead->pNext;
 while (pNode)
 {
 printf("%d\n", pNode->data);
 pNode = pNode->pNext;
 }
}
/************************************
@ Brief:  Free list memory 
@ Author: woniu201
@ Return:
************************************/
void  list_destory(list* pHead)
{
 list* pCur = pHead;
 list* pNext = pHead->pNext;
 while (pNext)
 {
 pNext = pNext->pNext;
 free(pCur);
 pCur = NULL;
 pCur = pNext;
 }
}

main c test

#include <stdio.h>
#include "list_head.h"
int main()
{
 list* pHead = list_create();
 int data1 = 1;
 int data2 = 3;
 int data3 = 2;
// int ret = list_insert_at(pHead,0, &data1);
// ret = list_insert_at(pHead, 1, &data2);
// if (ret == INDEXFAIL)
// {
//  printf(" Error adding index position \n");
// }
 list_order_insert(pHead, &data2);
 list_order_insert(pHead, &data1);
 list_order_insert(pHead, &data3);
 list_delete_at(pHead, 3);
 int deleteData = 1;
 list_delete(pHead, &deleteData);
 list_display(pHead);
 list_destory(pHead);
 return 1;
}

conclusion