package LinearDSA;
/**
* @author lokman 17/09/2022
*
*/
public class Queue {
private ListNode front;
private ListNode rear;
private int length = 0;
public Queue() {
this.front = null;
this.rear = null;
}
private class ListNode {
private int data;
private ListNode next;
public ListNode(int data) {
this.data = data;
this.next = null;
}
}
public int length() {
return length;
}
public boolean isEmpty() {
return length == 0;
}
public void enqueue(int data) {
ListNode temp = new ListNode(data);
if (isEmpty()) {
front = temp;
} else {
rear.next = temp;
}
rear = temp;
length++;
}
public int dequeue() {
if(isEmpty()) {
System.out.println("Queue is empty");
}
int data = front.data;
front = front.next;
if(front == null) {
rear = null;
}
length--;
return data;
}
public void print() {
if (isEmpty()) {
return;
}
ListNode current = front;
while (current != null) {
System.out.print(current.data + "-->");
current = current.next;
}
System.out.println("null");
}
public static void main(String[] args) {
Queue queue = new Queue();
queue.enqueue(10);
queue.enqueue(20);
queue.enqueue(30);
queue.print();
queue.dequeue();
queue.print();
}
}
