链表主要功能实现

//linklist.h：定义链表结点和方法。  
#include<iostream>
using namespace std;

struct Node
{
    int val;
    Node *next;
    Node(int x) :val(x), next(NULL) {}
};

class LinkList
{
public:
    //构造函数  
 LinkList();
    //在链表头部插入结点  
 void InsertHead(int val);
    //插入结点  
 void Insert(int val, int pos);
    //删除结点  
 void Remove(int pos);
    //得到链表长度  
 int Length();
    //链表反序  
 void Reverse();
    //查找结点位置  
 void Find(int val);
    //打印链表  
 void Print();
    //从大到小排序  
 void Sort();
    //析构函数
 ~LinkList();
private:
    Node * head;
    int length;
};

//linklist.cpp：链表方法的实现。  
#include <iostream>  
#include "linklist.h"  
using namespace std;

LinkList::LinkList()
{
    head = NULL;
    length = 0;
}

LinkList::~LinkList()
{
    Node *temp;
    for (int i = 0; i < length; i++)
    {
        temp = head;
        head = head->next;
        delete temp;
    }
}

int LinkList::Length()
{
    return length;
}

void LinkList::InsertHead(int val) {
    Insert(val, 0);
}

void LinkList::Insert(int val, int pos) {
    if (pos < 0)
    {
        cout << "The index must be larger than 0!" << endl;
        return;
    }
    int index = 1;
    Node *temp = head;
    Node *node = new Node(val);
    if (pos == 0)
    {
        node->next = head;
        head = node;
        length++;
        return;
    }
    while (temp != NULL && index < pos)
    {
        temp = temp->next;
        index++;
    }
    if (temp == NULL)
    {
        cout << "Fail to insert it!" << endl;
        return;
    }
    node->next = temp->next;
    temp->next = node;
    length++;
    return;
}

void LinkList::Remove(int pos)
{
    if (pos < 0 || length < 1)
    {
        cout << "The index must be larger than 0!" << endl;
        return;
    }
    int index = 1;
    Node *temp = head;
    if (pos == 0 && length == 1)
    {
        head = NULL;
        length--;
        return;
    }
    if (pos == 0 && length > 1)
    {
        head = temp->next;
        length--;
        return;
    }
    while (temp != NULL && index < pos)
    {
        temp = temp->next;
        index++;
    }

    if (temp&&temp->next&&temp->next->next)
    {
        temp->next = temp->next->next;
        length--;
        return;
    }
    cout << "Fail to delete it" << endl;
    return;
}
void LinkList::Sort()
{
    if (length <= 1)
        return;
    Node *i = head;
    for (; i != NULL; i = i->next)
        for (Node *j = i; j != NULL; j = j->next)
        {
            if (i->val > j->val)
            {
                int temp = i->val;
                i->val = j->val;
                j->val = temp;
            }
        }
    return;
}

void LinkList::Reverse()
{
    if (length <= 1)
        return;
    Node *pre = new Node(0);
    pre->next = head;
    Node *cur = head;
    while (cur&&cur->next)
    {
        Node *move = cur->next;
        cur->next = move->next;
        move->next = pre->next;
        pre->next = move;
    }
    head = pre->next;
    return;
}

void LinkList::Find(int val)
{
    if (length == 0)
    {
        cout << "Not found" << endl;
        return;
    }
    Node *p = head;
    int index = 1;
    int count = 0;
    while (p)
    {
        if (p->val == val)
        {
            cout << index++ << " ";
            p = p->next;
            count++;
        }
        else
        {
            p = p->next;
            index++;
        }
    }
    if (count == 1)
        cout << "There is " << 1 << " found." << endl;
    else if (count > 1)
        cout << "There are " << count << " found." << endl;
    else
        cout << "Not found" << endl;;
    return;
}

void LinkList::Print()
{
    if (head == NULL)
    {
        cout << "This is an empty LinkList" << endl;
        return;
    }

    Node *p = head;
    while (p!=NULL)
    {
        cout << p->val << " ";
        p = p->next;
    }
    cout << endl;
    return;
}