C++学习笔记之单向链表

例子：

struct node {    int data;    node * next; };

next：指向下一个node类型的结构，连接node 的纽带

存放学生信息的链表节点

struct student {    int num;    char name[20];    char sex;    float score;    student * next;};

动态申请内存的方法

student *p=(student*) malloc(sizeof(student));  student * p = new student;

建立单向链表

• 声明一个链首指针变量head，并赋初值NULL(包含0个节点的链表)
• 动态分配一个新节点，将该节点链入链尾
• 重复上一步

例子1：建立链表，读入n个整数，每个整数作为一个新结点插入到链尾

#include <iostream>using namespace std;struct node  { int data;node * next;};node * createList(int n);int main() {int n;node * listHead = NULL;cout << "Please enter the number of nodes:";cin >> n;if (n > 0)listHead = createList(n);return 0;}node *createList(int n) {node *temp, *tail = NULL, *head = NULL ;int num;cin >> num;head = new node ;  // 为新节点动态分配内存if (head == NULL)  {cout << "No memory available!";return NULL;}else  {head->data = num;head->next = NULL;tail = head;}for ( int i = 0; i < n - 1; i ++)  {cin >> num;temp = new node ;  // 为新节点动态分配内存if (temp == NULL) {cout << "No memory available!";return head;}else{temp->data = num;temp->next = NULL;tail->next = temp;tail = temp;}}return head ;}

遍历链表

依次访问链表中的每个节点的信息 

head->data = 15;head->next->data = 15;

一般遍历方法

node * curNode = head;while (curNode )curNode = curNode->next;

例子2：编写一个函数，输出例1链表中各节点的data成员的值

void outputList(node * head){cout << "List: ";node *curNode = head;while ( curNode )  {cout << curNode->data;if (curNode ->next)cout << " -> ";curNode = curNode ->next;}cout << endl;return;}

例子3：编写一个函数，在例1的链表中查找包含指定整数的节点 

node * findData(int n, node * head){node *curNode = head;while ( curNode )  {if ( curNode->data == n)  {cout<<"Find "<<n<<" in the list."<<endl;return curNode;}curNode = curNode->next;}cout<<"Can't find "<<n<<" in the list."<<endl;return NULL;}

在链表中节点a之后插入节点c

(1) 指针cptr指向节点c,aptr指向节点a；

(2) 把a后继节点的地址赋给节点c的后继指针

    cptr->next＝aptr->next；

(3) 把c的地址赋给节点a的后继指针

    aptr->next=cptr;

例子4：编写一个函数，将输入的整数从小到大插入链表

node * insertData(int n, node * head){node *curNode = head;// 指向插入点的后节点node *preNode = NULL;// 指向插入点的前节点node *newNode = NULL;// 指向新建节点while ((curNode!=NULL)&&(curNode->data<n)) {preNode = curNode; // 后节点变为前节点curNode = curNode->next; }newNode = new node ;  if (newNode == NULL) {cout << "No memory available!";return head;}newNode->data = n;if (preNode == NULL) //插入到链表头{newNode->next = curNode; return newNode; }else  {preNode->next = newNode; newNode->next = curNode; return head; }}

从链表中删除一个节点c

(1)在链表中查找要删除的节点c，用指针cptr指向节点c;

(2)如果c有前驱节点(设为d,用指针dptr指向d)，则将d的后继指针指向c的后继节点：dptr->next=cptr->next

(3)释放c占用的空间

例子5：编写一个函数，删除链表中包含指定整数的节点

node * deleteData(int n, node * head) {node *curNode = head;// 指向当前节点node *preNode = NULL;// 指向当前节点的前驱节点  while (curNode && curNode->data != n)   {  preNode = curNode; // 当前节点变为前驱节点  curNode = curNode->next;   }  if (curNode == NULL)   {  cout<<"Can't find "<<n<<" in the list"<<endl;  return head;  }  if (preNode == NULL) //删除链首节点  head = head->next;   else  preNode->next = curNode->next;   delete curNode;  return head;// 返回链首指针}