用C++实现链表的操作

#include <iostream>
using namespace std;
class Node
{
private:
int data;    // different data type for other apps
Node *next;  // the link pointer to next item
   public: 
   Node(int x=0,Node * ptr=NULL){data=x;}// constructor  构造函数
int getData( );
Node *getNext( );
void setData(int x);
void setNext(Node *ptr);
};

int Node::getData()
{
return data;
}

Node* Node::getNext()
{
return next;
}

void Node::setData(int x)
{
data = x;
}

void Node::setNext(Node* ptr)
{
next = ptr;
}


class List {
   private:
Node *head_ptr; Node *tail_ptr; int numOfItems;
   public: 
List( ); 
void initial(int a[], int n);//创建一个链表
// constructor
int size( );       Node *getHead( );      Node *getTail( );
bool isEmpty( );
Node *search(int x);  
//Node *itemAt(int position);
void removeHead();      
void removeTail(); 
void remove(int x); // delete leftmost item having x
void insertHead(int x);   
void insertTail(int x); 
void insert( int x,int y); 
};
List::List()
{
tail_ptr = NULL;
numOfItems = 0;
}