Java data Structure--implementing stacks with linked lists

=================================================//File name:linkstack_demo//-------------------------------- ----------------------------------------------//author:common//class name: link_long//attribute://Method: Class link_long{//chain node classes Publ IC Long ddata;public Link_long next;//a reference to the next node in the list public Link_long (long DData) {super (); this.ddata = DData;} public void DisplayLink () {//Displays the value of the current node System.out.println ("DData" +ddata);}} Class Name: linklist_long//property://Method: Class Linklist_long{private Link_long first;//only need the first node, from the first node to locate all nodes public linklist _long () {//constructor this.first = null;} public Boolean isEmpty () {return (first = = null);} public void Insertfirst (long dd) {//Insert element is inserted from the head of the linked list Link_long NewLink = new Link_long (dd); newlink.next = First;first = Newli NK;} Public long Deletefirst () {//delete Temp.ddatalink_long temp = first;//Staging Firstfirst = first.next;//Set next to Firstreturn temp.ddata;//returns the original first}public void Displaylist () {System.out.println ("List (first-->last):"); Link_long current = first;//is used to continuously change the position of the traverse while (CurreNT! = null) {Current.displaylink (); current = Current.next;}} Public Link_long find (int key) {//find the specified keyword Link_long current = First;while (current.ddata! = key) {if (Current.next = = null) return null;elsecurrent = Current.next;} return current;} Public Link_long Delete (int key) {///If the value of current matches, delete link_long current = first; Link_long previous = first;//does not match to the value while (current.ddata! = key) {if (Current.next = null) return null;else{// Pre and cur move backwards previous = Current;current = Current.next;}} Match to value if (current = = first)//only one first and match, then set first to First.nextfirst = first.next;else//current value matches, then delete, and assign cur next to the pre Nextprevious.next = Current.next;return Current;}} Class Name: linklist_long//property://Method: Class linkstack{//with a linked list implementation of the stack, the list is inserted from first, the new element will become first, delete the later element private Linklist_long Thelist;public Linkstack () {//constructor thelist = new Linklist_long ();} public void push (long j) {//In the stack, that is, the first INSERT element in the list Thelist.insertfirst (j);} Public long Pop () {//out of the stack, that is, delete the first element of the list return Thelist.deletefirst ();} public Boolean isEmpty () {//Determines whether the stack is empty, that is, whether the linked list is empty return (Thelist.isempty ());} public void Displaystack () {System.out.println ("Stack (Top-->bottom):"); Thelist.displaylist ();}} Main class//function:linkstack_demopublic class Linkstack_demo {public static void main (string[] args) {//TODO auto-generated method Stub linkstack thestack = new Linkstack (); Thestack.push (n); Thestack.push (+); Thestack.push (+); thestack.displaystack (); Thestack.pop (); Thestack.pop (); Thestack.displaystack ();}}

Java data Structure--implementing stacks with linked lists