双向链表 – 数据结构

最后更新于:2022-04-01 20:05:55

双向链表就是在单项链表的基础上增加了一个前向指针域。基本操作还是一样的,该双向链表是带有头节点的,最后一个节点的next指针域是为空的,不是指向首节点的。 双向链表的结构定义 ~~~ typedef char datatype; typedef struct node { datatype data; struct node *prior, *next; }linknode; typedef linknode *linklist; ~~~ 创建一个链表 ~~~ linklist CreatDlist(void) { char ch; linklist head; linknode *p, *h, *r; head = (linknode *)malloc(sizeof(linknode)); head->next = NULL; h = head; r = head; while((ch = getchar()) != '\n') { p = (linknode *)malloc(sizeof(linknode)); p->data = ch; p->next = NULL; if(r == head) { r->next = p; } else { r->next = p; r->prior = h; h = h->next; } r = p; } return head; } ~~~ 找到链表中一个节点 ~~~ linknode * GetNode(linklist head, int i) { linknode *p = head; int j = 0; while(p && jnext; j++; } return p; } ~~~ 插入一个节点 ~~~ void InsetDlist(linklist head, datatype ch, int i) { linknode *p = head->next, *t; int j = 0; while(p && j < i-1) { p = p->next; j++; } t = (linknode *)malloc(sizeof(linknode)); t->data = ch; t->prior = p; t->next = p->next; p->next = t; t->next->prior = t; } ~~~ 删除一个节点 ~~~ void DeleteDlist(linklist head, int i) { linknode *p = head->next; int j = 0; while(p && j < i-1) { p = p->next; j++; } p->next->prior = p->prior; p->prior->next = p->next; puts("a"); free(p); } ~~~ 显示整个双向链表 ~~~ void ShowDlist(linklist head) { linknode *p = head; while(p) { printf("%c", p->data); p = p->next; } putchar('\n'); } ~~~ 释放整个双向链表 ~~~ void FreeDlist(linklist head) { linknode *p; int i = 0; p = head; while(p) { free(p); head = head->next; p = head; i++; } printf("\nthe dlist free is ok.the node has %d.\n", i); } ~~~ 双向链表的测试程序 ~~~ #include #include #include "dlist.h" void show(linknode *p) { printf("p->prior:%c\n", p->prior->data); printf("p->data:%c\n", p->data); printf("p->next:%c\n", p->next->data); } int main(void) { linklist head; //linknode *p; head = CreatDlist(); ShowDlist(head->next); p = GetNode(head, 3); show(p); DeleteDlist(head, 3); p = GetNode(head, 3); show(p); InsetDlist(head, 'x', 2); ShowDlist(head->next); FreeDlist(head); return 0; } ~~~
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