单链表逆向 c

单链表逆向

#include <stdio.h>#include <stdlib.h>struct node {int data;struct node * next;};//带头结点的单链表struct node * create_list(){struct node * head = NULL;head = (struct node *)malloc(sizeof(struct node));if (head == NULL){printf("malloc error!/n");return NULL;}head->data = 0;head->next = NULL;return head;}//在头结点之后插入新结点int insert_node(struct node * head, int num){//分配新结点struct node * new_node = NULL;new_node = (struct node * )malloc(sizeof(struct node));if (new_node == NULL){printf("malloc error!/n");return -1;}new_node->data = num;//在头结点之后插入新结点new_node->next = head->next;head->next = new_node;return 0;}//显示所有结点void show_list(struct node * head){struct node * head_t = head->next;while(head_t != NULL){printf("%d/n",head_t->data);head_t = head_t->next;}}//链表中的结点数int count_list(struct node * head){struct node * head_t = head->next;int i = 0; //此处局部变量如果没有初始化竟然也会出问题while(head_t != NULL){i++;head_t = head_t->next;}return i;}//链表逆向struct node * revert_list(struct node * head){struct node * prev = head;struct node * pmid = head->next;struct node * pnext = head->next;//空链表或只有一个结点不用逆向if ( (head->next== NULL) || count_list(head)==1 ){return head;}//进行链表的逆向while(pnext->next != NULL){pnext = pnext->next;pmid->next = prev;prev = pmid;pmid = pnext;}//处理链表头和链表尾head->next->next = NULL;head->next = pnext;pnext->next = prev;return 0;}//删除操作int delete_node(struct node * head, int num){struct node * temp = head->next;struct node * prev = head;//寻找删除的结点while (temp){if (num == temp->data)break;prev = temp;temp = temp->next;}//没有找到if(temp == NULL){printf("cann't find !/n");return -1;}//删除结点prev->next = temp->next;free(temp);return 0;}int main(int argc, char* argv[]){struct node * head = NULL;head = create_list();insert_node(head, 1);insert_node(head, 2);insert_node(head, 3);insert_node(head, 4);insert_node(head, 5);insert_node(head, 6);show_list(head);printf("revert_list/n");revert_list(head);show_list(head);printf("after delete/n");delete_node(head,3);show_list(head);}