C++ 单链表的基本操作(详解)

#include "stdafx.h"
#include "SingleList.h"
#include <cstdlib>
#include <iostream>
#include <string.h>
#include <conio.h>
#include <stdio.h>

/*c++实现简单的单链表操作*/
using namespace std;

SingleList::SingleList()
{
  int num;
  char name[128];

  // 创建链表
  node *stuList = CreatNode();
  PrintList(stuList);

  // 插入节点
  printf("\n请输入要插入的学生学号和姓名，输入0 0表示结束.");
  scanf_s("%d%s", &num, name, 100);
  stuList = InsertNode(stuList, num, name);
  PrintList(stuList);

  // 删除节点
  printf("\n请输入要删除的学生学号：");
  scanf_s("%d", &num, 100);
  stuList = DeleteNode(stuList, num);
  PrintList(stuList);

  // 逆序
  printf("\n逆序后的链表为：\n");
  stuList = ReverseList(stuList);
  PrintList(stuList);

  system("PAUSE");
}


SingleList::~SingleList()
{
}

//建立单链表 
node *SingleList::CreatNode()
{
  node *head, *p, *s;

  int num = 0;
  char name[128];
  int cycle = 1;

  head = (node *)malloc(sizeof(node));  // 为头结点分配内存空间
  head->next = nullptr;
  p = head;    // p指向头节点

  while (cycle)
  {
    printf("\n请输入学生的学号和姓名:");
    scanf_s("%d%s", &num, name, 100);

    if (num != 0)
    {
      s = (node *)malloc(sizeof(node));
      s->num = num;
      memcpy(s->name, name, 128);
      printf("%d%s", s->num, s->name);
      p->next = s;    // 指向新插入的节点
      p = s;    // p指向当前节点
    }
    else
    {
      cycle = 0;
    }
  }

  head = head->next;
  p->next = NULL;
  printf("头节点学生信息为: %d%s\n", head->num, head->name);

  return head;
}

//单链表插入
node *SingleList::InsertNode(node *head, int num, char* name)
{
  node *s, *p1, *p2 = NULL;

  p1 = head;
  s = (node *)malloc(sizeof(node));
  s->num = num;
  strcpy_s(s->name, name);

  while ((s->num > p1->num) && p1->next != NULL)
  {
    p2 = p1;
    p1 = p1->next;
  }

  if (s->num <= p1->num)
  {
    if (head == p1)
    {
      // 插入首节点
      s->next = p1;
      head = s;
    }
    else
    {
      // 插入中间节点
      p2->next = s;
      s->next = p1;
    }
  }
  else
  {
    // 插入尾节点
    p1->next = s;
    s->next = NULL;
  }

  return head;
}

// 计算单链表长度
int SingleList::GetLength(node *head)
{
  int length = 0;
  node *p;
  p = head;

  while (p != NULL)
  {
    p = p->next;
    length++;
  }
  return length;
}

//单链表删除某个元素 
node *SingleList::DeleteNode(node *head, int num)
{
  node *p1, *p2 = nullptr;
  p1 = head;

  while (num != p1->num && p1->next != NULL)
  {
    p2 = p1;
    p1 = p1->next;
  }

  if (num == p1->num)
  {
    if (p1 == head)
    {
      head = p1->next;
    }
    else
    {
      p2->next = p1->next;
    }
    free(p1);
  }
  else
  {
    printf("找不到学号为%d 的学生!\n", num);
  }
  return head;

}

//单链表逆序
node *SingleList::ReverseList(node *head)
{
  // A->B->C->D
  node *old_head;    // 原来链表的头
  node *new_head;    // 新链表的头
  node *cur_head;    // 获得原来链表的头

  if (head == NULL || head->next == NULL)
    return head;

  new_head = head;        // A
  cur_head = head->next;    // B
  while (cur_head)
  {
    old_head = cur_head->next;    // 将原来链表的头取出，并将第二个节点作为头节点
    cur_head->next = new_head;  // 将取出的头设为新链表的头
    new_head = cur_head;        // 新链表的头就是目前新链表的头
    cur_head = old_head;          // 接着处理
  }
  head->next = NULL;
  head = new_head;
  return head;
}

//打印单链表
void SingleList::PrintList(node *head)
{
  node *p;
  int n;
  n = GetLength(head);
  printf("\n打印出 %d 个学生的信息:\n", n);

  p = head;
  while (p != NULL)
  {
    printf("学号： %d ，姓名： %s\n", p->num, p->name);
    p = p->next;
  }
}

#pragma once
typedef struct student
{
  int num;        // 学号
  char name[128]; // 姓名
  struct student *next;
}node;

class SingleList
{
public:
  SingleList();
  ~SingleList();

  //建立单链表 
  node *CreatNode();
  //单链表插入
  node *InsertNode(node *head, int num, char* name);
  // 计算单链表长度
  int GetLength(node *head);
  //单链表删除某个元素 
  node *DeleteNode(node *head, int num);
  //单链表逆序
  node *ReverseList(node *head);
  //打印单链表
  void PrintList(node *head);

};