Mega Code Archive
A Queue Implemented by a Linked List
<![CDATA[
class Link {
public int iData;
public Link next;
public Link(int id) {
iData = id;
}
public String toString() {
return "{" + iData + "} ";
}
}
class LinkList {
private Link first;
public LinkList() {
first = null;
}
public boolean isEmpty() {
return (first == null);
}
public void insertFirst(int dd) {
Link newLink = new Link(dd);
newLink.next = first;
first = newLink;
}
public int deleteFirst() {
Link temp = first;
first = first.next;
return temp.iData;
}
public String toString() {
String str = "";
Link current = first;
while (current != null) {
str += current.toString();
current = current.next;
}
return str;
}
}
class FirstLastList {
private Link first;
private Link last;
public FirstLastList() {
first = null;
last = null;
}
public boolean isEmpty() {
return first == null;
}
public void insertFirst(int dd) {
Link newLink = new Link(dd);
if (isEmpty())
last = newLink;
newLink.next = first;
first = newLink;
}
public void insertLast(int dd) {
Link newLink = new Link(dd);
if (isEmpty())
first = newLink;
else
last.next = newLink;
last = newLink;
}
public int deleteFirst() {
int temp = first.iData;
if (first.next == null)
last = null;
first = first.next;
return temp;
}
public String toString() {
String str = "";
Link current = first;
while (current != null) {
str += current.toString();
current = current.next;
}
return str;
}
}
class LinkQueue {
private FirstLastList theList;
public LinkQueue() {
theList = new FirstLastList();
}
public boolean isEmpty() {
return theList.isEmpty();
}
public void insert(int j) {
theList.insertLast(j);
}
public double remove() {
return theList.deleteFirst();
}
public String toString() {
return theList.toString();
}
}
public class MainClass {
public static void main(String[] args) {
LinkQueue theQueue = new LinkQueue();
theQueue.insert(20);
theQueue.insert(40);
System.out.println(theQueue);
theQueue.insert(60);
theQueue.insert(80);
System.out.println(theQueue);
theQueue.remove();
System.out.println(theQueue);
}
}
{20} {40}
{20} {40} {60} {80}
{60} {80}
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