C語言學習之單向鏈表操作

該文件爲單向鏈表操作的一些接口：（如發現有錯誤的地方，及時告知，不勝感激！）

list.h

#ifndef  _CHAINLIST_H_
#define  _CHAINLIST_H_

typedef struct
{
    char key[15];
    char name[20];
    int age;
}DATATYPE_T;

typedef struct Node
{
    DATATYPE_T  data;
    struct Node *next;
}chainListType;

/* 添加節點到鏈表末尾 */
chainListType *chainlist_add_end(chainListType *head,DATATYPE_T data);

/* 添加節點到鏈表首部 */
chainListType *chainlist_add_first(chainListType *head,DATATYPE_T data);

/* 按關鍵字在鏈表中查找內容 */
chainListType *chainlist_find(chainListType *head,char *key);

/* 插入節點到鏈表指定位置 */
chainListType *chainlist_insert(chainListType *head,char *findkey,DATATYPE_T data);

/* 刪除指定關鍵字的節點 */
chainListType *chainlist_delete(chainListType *head,char *key);

/*獲取鏈表的節點數量 */
int chainlist_length(chainListType *head);

#endif

list.c文件如下：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "chainlist.h"

chainListType *chainlist_add_end(chainListType *head,DATATYPE_T data)
{
    chainListType *node,*phead;

    node = malloc(sizeof(chainListType));
    if(NULL == node)
    {
        printf("malloc failed\n");
        return NULL;
    }
    node->data = data;
    node->next = NULL;
    if(head ==NULL)
    {
        head = node;
        return head;
    }
    phead = head;
   
    while(phead->next != NULL)
    {
        phead = phead->next;
    }
    phead->next = node;

    return head;
}

chainListType *chainlist_add_first(chainListType *head,DATATYPE_T data)
{
    chainListType *node;

    node = malloc(sizeof(chainListType));
    if(NULL == node)
    {
        printf("malloc failed\n");
        return NULL;
    }
    node->data = data;
    node->next = head;
    head = node;

    return head;
}

chainListType *chainlist_find(chainListType *head,char *key)
{
    chainListType *phead;
    phead = head;
   
    while(phead)
    {
        if(strcmp(phead->data.key,key)==0)
        {
            return phead;
        }
        phead = phead->next;
    }
    return NULL;
}

chainListType *chainlist_insert(chainListType *head,char *findkey,DATATYPE_T data)
{
    chainListType *node,*node1;
   
    node = malloc(sizeof(chainListType));
    if(NULL == node)
    {
        printf("malloc failed\n");
        return NULL;
    }

    node->data = data;
    node1 = chainlist_find(head,findkey);   
    if(node1)
    {
        node1->next = node->next;
        node1->next = node;
    }
    else
    {
        free(node);
        printf("can't find key\n");
    }
    return head;
}

chainListType *chainlist_delete(chainListType *head,char *key)
{
    chainListType *node,*phead;
    node = head;
    phead = head;
   
    while(phead)
    {
        if(strcmp(head->data.key,key)==0)
        {
            node = head->next;
            free(head);
            head = NULL;
            head = node;
            if(head!=NULL)
            {
                return head;
            }
            else
            {
                return NULL;
            }
        }
        if(strcmp(phead->data.key,key)==0)
        {
            node->next = phead->next;
            free(phead);
            phead = NULL;
            return head;
        }
        else
        {
            node = phead;
            phead = phead->next;
        }
    }
    return NULL;
}

int chainlist_length(chainListType *head)
{
    int length = 0;
    chainListType *phead;

    phead = head;
    while(phead)
    {
        phead = phead->next;
        length++;
    }

    return length;
}