单链表操作

程序有问题，需改进。

#include <iostream>using namespace std;typedef struct NODE{int data;NODE *next;}node;//create a list.node *create(){node *head, *first, *second;head = new(node);first = head;int num;cout << "Now input the list:\n";while(cin >> num && num){cout << "number:" << num << endl;second = new(node);second->data = num;first->next = second;second->next = NULL;first = second;}if(first - head == 0)return NULL;head = head->next;return head;}//打印链表.void printList(node *head){cout << "Now output the list:\n";//list is null.if(head == NULL)return ;//list is not null.else{node *p = head;while(p != NULL){cout << p->data << " ";p = p->next;}cout << endl;}}//删除节点.node *deleteNode(node *head, int num){node *first, *second;first = head;while(num != first->data && first->next != NULL){second = first;first = first->next;}//---找到了要删除的节点.if(num == first->data){//头结点.if(first == head)head = head->next;//不是头结点.elsesecond->next = first->next;free(first);}//---没有找到要删除的节点.elsecout << "can not find the node!\n";return head;}//插入节点.node *insertNode(node *head,int num){node *newNode = new(node);newNode->data = num;node *first = head, *second;while(num > first->data && first->next != NULL){second = first;first = first->next;}//---未达到链表结尾,即在链表头部或内部插入节点.if(num <= first->data){//插入头结点之前.if(first == head){newNode->next = head;head = newNode;}//插入头结点之后.else{newNode->next = first;second->next = newNode;}}//---达到链表结尾，即在链表尾部插入.else{first->next = newNode;newNode->next = NULL;//注意将为节点的指针置为空.}return head;}//求链表长度.int len(node *head){int cnt = 0;node *index = head;while(index != NULL){cnt++;index = index->next;}return cnt;}//单链表排序.node *sort(node *head){if(head == NULL || head->next == NULL)return NULL;node *first = head;node *second = head->next;int n = len(head);cout << "the lenth is: " << len(head) << endl << endl;int temp;for(int i = 1;i < n;i++){//第i趟比较.for(int j = 1;j < n-i;j++ ){if(first->data > second->data){temp = first->data;first->data = second->data;second->data = temp;}first = first->next;second = second->next;}}return head;}int main(){node *p = create();cout << endl << "*p:" << *p->data << endl;printList(p);p = deleteNode(p,5);printList(p);p = sort(p);printList(p);p = insertNode(p,8);printList(p);return 0;}