数据结构——c双向链表实现

不带头结点

#include<stdlib.h>

typedef struct _tlist{
    int data;
    struct _tlist *prior;
    struct _tlist *next;
} *TList, TNode;

void initTList(TList *l)
{
    *l = NULL;
}

void insertToHead(TList *l, int val)
{
    TList temp = (TList)malloc(sizeof(TNode));
    TList t = *l;
    
    // 如果链表为NULL
    if(t == NULL)
    {
        temp->data = val;
        temp->prior = NULL;
        temp->next = NULL;
        *l = temp;

        return;
    }
    
    temp->data = val;
    temp->prior = NULL;
    temp->next = t;
    t->prior = temp;
    
    *l = temp;
}

void insertToTail(TList *l, int val)
{
    TList temp = (TList)malloc(sizeof(TNode));
    TList t = *l;

    if(t == NULL)
    {
        temp->data = val;
        temp->prior = NULL;
        temp->next = NULL;
        *l = temp;

        return;
    }

    temp->data = val;
    // 找到旧双向链表的最后一个结点,t 指向最后一个结点
    // 使用 t && t->next 条件
    while(t && t->next)
        t = t->next;
    t->next = temp;
    temp->prior = t;
    temp->next = NULL;    
}

void deleteTListHead(TList *l)
{
    if(*l == NULL)
        return;

    TList t = *l;    // t指向头结点
    *l = t->next;

    free(t);
}

void printTList(TList l, const char* str)
{
    if(str != NULL)
        printf("%s\n",str);

    while(l)
    {
        printf("%3d", l->data);
        l = l->next;
    }

    printf("\n");
}

运行结果如下：

$ ./TList 
从双向链表头部插入5，6
  6  5
从双向链表尾部插入7，8
  6  5  7  8
删除双向链表的第一个结点
  5  7  8