Object-oriented basics: Improvement of linked lists

Use internal classes to complete linked list operations 1. Add nodes and add the [java] class Link {// linked list completion class Node {// save each Node at the end of the linked list, in this example, private String data is defined as an internal class for convenience. // you can save the content of a Node, private Node next. // you can save the next public Node (String data) {this. data = data; // set the Node content through the constructor} public void add (Node newNode) {// add the Node to the appropriate location if (this. next = null) {// if the next node is empty, set the new node to the next position this. next = newNode;} else {// if it is not empty, you need to continue searching for next this. next. add (newNode) ;}} p Ublic void print () {System. out. print (this. data + "\ t"); // output the node content if (this. next! = Null) {// there is another element. You need to output this. next. print (); // The next Node continues to call print }}; private Node root; // a root Node public void addNode (String data) must exist in the linked list) {// Add Node newNode = new Node (data); // define a new Node if (this. root = null) {// No root node this. root = newNode; // set the first node to the root node} else {// not the root node, Put it after the last node this. root. add (newNode); // automatically arrange the location of this Node through Node} public void printNode () {// output all the contents of the linked list if (this. root! = Null) {// if the root element is not empty this. root. print (); // call the output operation in the Node class }}; public class LinkDemo02 {public static void main (String args []) {Link l = new Link (); l. addNode ("A"); // Add node l. addNode ("B"); // Add node l. addNode ("C"); // Add node l. addNode ("D"); // Add node l. addNode ("E"); // Add node l. printNode () ;}; 2. Search for nodes in a recursive manner to find the complete class Node of the [java] class Link {// chain table {// save each Node, to facilitate the definition of private String data; // Save the content of the Node private Node next; // save the next Node public Node (String data) {this. data = data; // set the Node content through the constructor} public void add (Node newNode) {// add the Node to the appropriate location if (this. next = null) {// if the next node is empty, set the new node to the next position this. next = newNode;} else {// if it is not empty, you need to continue searching for next this. next. add (newNode) ;}} public void print () {System. out. print (this. data + "\ t"); // output node content if (this. next! = Null) {// there is another element. You need to output this. next. print (); // The next node continues to call print} public boolean search (String data) {// internal search method if (data. equals (this. data) {// determine whether the input data is consistent with the data of the current node return true;} else {// continue to judge if (this. next! = Null) {// if the next node exists, continue to search for return this. next. search (data); // return the next query result} else {return false; // If NO content is equal after all nodes are queried, returns false }}}; private Node root; // a root Node public void addNode (String data) must exist in the linked list) {// Add Node newNode = new Node (data); // define a new Node if (this. root = null) {// No root node this. root = newNode; // set the first node to the root node} else {// not the root node, Put it after the last node this. root. add (newNode); // automatically arrange the location of this Node through Node }} Public void printNode () {// output all contents of the linked list if (this. root! = Null) {// if the root element is not empty this. root. print (); // call the output operation in the Node class} public boolean contains (String name) {// determine whether the element has return this. root. search (name); // call the search method} in the Node class; public class LinkDemo02 {public static void main (String args []) {Link l = new Link (); l. addNode ("A"); // Add node l. addNode ("B"); // Add node l. addNode ("C"); // Add node l. addNode ("D"); // Add node l. addNode ("E"); // Add node System. out. println (l. con Teains ("C") ;}; 3. delete a node, change the address passed by the reference [java] class Link {// complete class Node of the linked list {// save each Node, which is directly defined as an internal class private String data for convenience; // Save the content of the Node private Node next; // save the next Node public Node (String data) {this. data = data; // set the Node content through the constructor} public void add (Node newNode) {// add the Node to the appropriate location if (this. next = null) {// if the next node is empty, set the new node to the next position this. next = newNode;} else {// if it is not empty, you need to continue searching for next this. next. add (newNode );} Public void print () {System. out. print (this. data + "\ t"); // output the node content if (this. next! = Null) {// there is another element. You need to output this. next. print (); // The next node continues to call print} public boolean search (String data) {// internal search method if (data. equals (this. data) {// determine whether the input data is consistent with the data of the current node return true;} else {// continue to judge if (this. next! = Null) {// if the next node exists, continue to search for return this. next. search (data); // return the next query result} else {return false; // If NO content is equal after all nodes are queried, returns false }}public void delete (Node previous, String data) {if (data. equals (this. data) {// matched node previous is found. next = this. next; // empty current node} else {if (this. next! = Null) {// The next node still exists this. next. delete (this, data); // continue searching }}}; private Node root; // a root Node public void addNode (String data) must exist in the linked list) {// Add Node newNode = new Node (data); // define a new Node if (this. root = null) {// No root node this. root = newNode; // set the first node to the root node} else {// not the root node, Put it after the last node this. root. add (newNode); // automatically arrange the location of this Node through Node} public void printNode () {// output all the contents of the linked list if (this. root! = Null) {// if the root element is not empty this. root. print (); // call the output operation in the Node class} public boolean contains (String name) {// determine whether the element has return this. root. search (name); // call the search method in the Node class} public void deleteNode (String data) {// delete a Node if (this. contains (data) {// determines whether a node exists. // you must determine whether the element is currently equal to the root element if (this. root. data. equals (data) {// The content is the root node this. root = this. root. next; // modify the root node and set the first node to the root node} else {this. root. next. delete (root, data); // pass in the previous node and data of the next node together }}}; public class LinkDemo02 {public static void main (String args []) {Link l = new Link (); l. addNode ("A"); // Add node l. addNode ("B"); // Add node l. addNode ("C"); // Add node l. addNode ("D"); // Add node l. addNode ("E"); // Add node System. out. println ("======= before deletion ========"); l. printNode (); // System. out. println (l. contains ("X"); l. deleteNode ("C"); // delete node l. deleteNode ("D"); // delete node l. deleteNode ("A"); // Delete the node System. out. println ("\ n ======= after deletion =========="); l. printNode (); System. out. println ("\ n query node:" + l. contains ("B "));}};