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Difference between a Static Queue and a Singly Linked List

  • Difficulty Level : Easy
  • Last Updated : 27 May, 2021

Static Queue: A queue is an ordered list of elements. It always works in first in first out(FIFO) fashion. All the elements get inserted at the REAR and removed from the FRONT of the queue. In implementation of the static Queue, an array will be used so all operation of queue are index based which makes it faster for all operations except deletion because deletion requires shifting of all the remaining elements to the front by one position.
A Static Queue is a queue of fixed size implemented using array.
 

 

Singly Linked List: A linked list is also an ordered list of elements. You can add an element anywhere in the list, change an element anywhere in the list, or remove an element from any position in the list. Each node in the list stores the content and a pointer or reference to the next node in the list. To store a single linked list, only the reference or pointer to the first node in that list must be stored. The last node in a single linked list points to nothing (or null).
 



Here are some of the major differences between a Static Queue and a Singly Linked List 
 

Static QueueSingly Linked List
Queue is a collection of one or more elements arranged in memory in a contiguous fashion. 
 
A linked list is a collection of one or more elements arranged in memory in a dis-contiguous fashion. 
 
Static Queue is always fixed size. 
 
List size is never fixed. 
 
In Queue, only one and single type of information is stored because static Queue implementation is through Array. 
 
List also stored the address for the next node along with it’s content. 
 
Static Queue is index based. 
 
Singly linked list is reference based. 
 
Insertion can always be performed on a single end called REAR and deletion on the other end called FRONT
 
Insertion as well as deletion can performed any where within the list. 
 
Queue is always based on FIFO. 
 
List may be based on FIFI or LIFO etc. 
 
Queue have two pointer FRONT and REAR. 
 
While List has only one pointer basically called HEAD. 
 

Below is the implementation of a Static Queue
 

Java




// Java program to implement a queue using an array
class Queue {
    private static int front, rear, capacity;
    private static int queue[];
 
    Queue(int c)
    {
        front = rear = 0;
        capacity = c;
        queue = new int[capacity];
    }
 
    // function to insert an element
    // at the rear of the queue
    static void queueEnqueue(int data)
    {
        // check queue is full or not
        if (capacity == rear) {
            System.out.printf("\nQueue is full\n");
            return;
        }
 
        // insert element at the rear
        else {
            queue[rear] = data;
            rear++;
        }
        return;
    }
 
    // function to delete an element
    // from the front of the queue
    static void queueDequeue()
    {
        // if queue is empty
        if (front == rear) {
            System.out.printf("\nQueue is empty\n");
            return;
        }
 
        // shift all the elements from index 2 till rear
        // to the right by one
        else {
            for (int i = 0; i < rear - 1; i++) {
                queue[i] = queue[i + 1];
            }
 
            // store 0 at rear indicating there's no element
            if (rear < capacity)
                queue[rear] = 0;
 
            // decrement rear
            rear--;
        }
        return;
    }
 
    // print queue elements
    static void queueDisplay()
    {
        int i;
        if (front == rear) {
            System.out.printf("\nQueue is Empty\n");
            return;
        }
 
        // traverse front to rear and print elements
        for (i = front; i < rear; i++) {
            System.out.printf(" %d <-- ", queue[i]);
        }
        return;
    }
 
    // print front of queue
    static void queueFront()
    {
        if (front == rear) {
            System.out.printf("\nQueue is Empty\n");
            return;
        }
        System.out.printf("\nFront Element is: %d", queue[front]);
        return;
    }
}
 
public class StaticQueueinjava {
 
    // Driver code
    public static void main(String[] args)
    {
        // Create a queue of capacity 4
        Queue q = new Queue(4);
 
        // print Queue elements
        q.queueDisplay();
 
        // inserting elements in the queue
        q.queueEnqueue(20);
        q.queueEnqueue(30);
        q.queueEnqueue(40);
        q.queueEnqueue(50);
 
        // print Queue elements
        q.queueDisplay();
 
        // insert element in the queue
        q.queueEnqueue(60);
 
        // print Queue elements
        q.queueDisplay();
 
        q.queueDequeue();
        q.queueDequeue();
        System.out.printf("\n\nafter two node deletion\n\n");
 
        // print Queue elements
        q.queueDisplay();
 
        // print front of the queue
        q.queueFront();
    }
}

C#




// C# program to implement a queue using an array
using System;
     
public class Queue
{
    private static int front, rear, capacity;
    private static int []queue;
 
    public Queue(int c)
    {
        front = rear = 0;
        capacity = c;
        queue = new int[capacity];
    }
 
    // function to insert an element
    // at the rear of the queue
    public void queueEnqueue(int data)
    {
        // check queue is full or not
        if (capacity == rear)
        {
            Console.Write("\nQueue is full\n");
            return;
        }
 
        // insert element at the rear
        else
        {
            queue[rear] = data;
            rear++;
        }
        return;
    }
 
    // function to delete an element
    // from the front of the queue
    public void queueDequeue()
    {
        // if queue is empty
        if (front == rear)
        {
            Console.Write("\nQueue is empty\n");
            return;
        }
 
        // shift all the elements from index 2 till rear
        // to the right by one
        else
        {
            for (int i = 0; i < rear - 1; i++)
            {
                queue[i] = queue[i + 1];
            }
 
            // store 0 at rear indicating there's no element
            if (rear < capacity)
                queue[rear] = 0;
 
            // decrement rear
            rear--;
        }
        return;
    }
 
    // print queue elements
    public void queueDisplay()
    {
        int i;
        if (front == rear)
        {
            Console.Write("\nQueue is Empty\n");
            return;
        }
 
        // traverse front to rear and print elements
        for (i = front; i < rear; i++)
        {
            Console.Write(" {0} <-- ", queue[i]);
        }
        return;
    }
 
    // print front of queue
    public void queueFront()
    {
        if (front == rear)
        {
            Console.Write("\nQueue is Empty\n");
            return;
        }
        Console.Write("\nFront Element is: {0}", queue[front]);
        return;
    }
}
 
public class StaticQueueinjava
{
 
    // Driver code
    public static void Main(String[] args)
    {
        // Create a queue of capacity 4
        Queue q = new Queue(4);
 
        // print Queue elements
        q.queueDisplay();
 
        // inserting elements in the queue
        q.queueEnqueue(20);
        q.queueEnqueue(30);
        q.queueEnqueue(40);
        q.queueEnqueue(50);
 
        // print Queue elements
        q.queueDisplay();
 
        // insert element in the queue
        q.queueEnqueue(60);
 
        // print Queue elements
        q.queueDisplay();
 
        q.queueDequeue();
        q.queueDequeue();
        Console.Write("\n\nafter two node deletion\n\n");
 
        // print Queue elements
        q.queueDisplay();
 
        // print front of the queue
        q.queueFront();
    }
}
 
/* This code contributed by PrinciRaj1992 */
Output: 
Queue is Empty
 20 <--  30 <--  40 <--  50 <-- 
Queue is full
 20 <--  30 <--  40 <--  50 <-- 

after two node deletion

 40 <--  50 <-- 
Front Element is: 40

 

Below is the implementation of a Singly Linked List
 

Java




// Java program to implement singly linked list
class SinglyLList {
 
    class Node {
 
        // node variables
        int data;
        Node next;
 
        public Node(int data)
        {
            this.data = data;
            this.next = null;
        }
    }
 
    // create reference variable of Node
    Node head;
 
    // function to insert a node
    // at the beginning of the list
    void InsertAtStart(int data)
    {
        // create a node
        Node new_node = new Node(data);
 
        new_node.next = head;
        head = new_node;
    }
 
    // function to insert node
    // at the end of the list
    void InsertAtLast(int data)
    {
 
        Node new_node = new Node(data);
        if (head == null) {
            head = new_node;
            return;
        }
 
        new_node.next = null;
 
        Node last = head;
        while (last.next != null) {
            last = last.next;
        }
 
        last.next = new_node;
    }
 
    // function to delete a node
    // at the beginning of the list
    void DeleteAtStart()
    {
        if (head == null) {
            System.out.println("List is empty");
            return;
        }
        head = head.next;
    }
 
    // function to delete a node at
    // a given position in the list
    void DeleteAtPos(int pos) throws Exception
    {
        int position = 0;
        if (pos > Count() || pos < 0) {
            throw new Exception("Incorrect position exception");
        }
        Node temp = head;
        while (position != pos - 1) {
            temp = temp.next;
            position++;
        }
        temp.next = temp.next.next;
    }
 
    // function to delete a node
    // from the end of the list
    void DeleteAtLast()
    {
        Node delete = head;
        while (delete.next != null
               && delete.next.next != null) {
            delete = delete.next;
        }
        delete.next = null;
    }
 
    // function to display all the nodes of the list
    void Display()
    {
        Node disp = head;
        while (disp != null) {
            System.out.print(disp.data + "->");
            disp = disp.next;
        }
    }
 
    // function to return the total nodes in the list
    int Count()
    {
        int elements = 0;
        Node count = head;
        while (count != null) {
            count = count.next;
            elements++;
        }
        return elements;
    }
}
 
public class GFG {
 
    // Driver code
    public static void main(String[] args) throws Exception
    {
        // create object of class singlyList
        SinglyLList list = new SinglyLList();
 
        // insert elements of singly linked list
        // at beginning
        list.InsertAtStart(3);
        list.InsertAtStart(2);
        list.InsertAtStart(1);
 
        // print linked list elements
        list.Display();
 
        // insert element at the end of list
 
        list.InsertAtLast(1);
        System.out.println("\nafter inserting node at the end\n ");
 
        // print linked list elements
        list.Display();
 
        // delete an element at the given position
        list.DeleteAtPos(1);
 
        // delete starting element
        list.DeleteAtStart();
 
        // delete last element
        list.DeleteAtLast();
 
        System.out.println("\nafter deleting node: second, first and last\n ");
 
        // print linked list elements
        list.Display();
    }
}

C#




// C# program to implement singly linked list
using System;
 
public class SinglyLList
{
 
    public class Node
    {
 
        // node variables
        public int data;
        public Node next;
 
        public Node(int data)
        {
            this.data = data;
            this.next = null;
        }
    }
 
    // create reference variable of Node
    public Node head;
 
    // function to insert a node
    // at the beginning of the list
    public void InsertAtStart(int data)
    {
        // create a node
        Node new_node = new Node(data);
 
        new_node.next = head;
        head = new_node;
    }
 
    // function to insert node
    // at the end of the list
    public void InsertAtLast(int data)
    {
 
        Node new_node = new Node(data);
        if (head == null)
        {
            head = new_node;
            return;
        }
 
        new_node.next = null;
 
        Node last = head;
        while (last.next != null)
        {
            last = last.next;
        }
 
        last.next = new_node;
    }
 
    // function to delete a node
    // at the beginning of the list
    public void DeleteAtStart()
    {
        if (head == null)
        {
            Console.WriteLine("List is empty");
            return;
        }
        head = head.next;
    }
 
    // function to delete a node at
    // a given position in the list
    public void DeleteAtPos(int pos)
    {
        int position = 0;
        if (pos > Count() || pos < 0)
        {
            throw new Exception("Incorrect position exception");
        }
        Node temp = head;
        while (position != pos - 1)
        {
            temp = temp.next;
            position++;
        }
        temp.next = temp.next.next;
    }
 
    // function to delete a node
    // from the end of the list
    public void DeleteAtLast()
    {
        Node delete = head;
        while (delete.next != null
            && delete.next.next != null)
        {
            delete = delete.next;
        }
        delete.next = null;
    }
 
    // function to display all the nodes of the list
    public void Display()
    {
        Node disp = head;
        while (disp != null)
        {
            Console.Write(disp.data + "->");
            disp = disp.next;
        }
    }
 
    // function to return the total nodes in the list
    public int Count()
    {
        int elements = 0;
        Node count = head;
        while (count != null)
        {
            count = count.next;
            elements++;
        }
        return elements;
    }
}
 
class GFG
{
 
    // Driver code
    public static void Main(String[] args)
    {
        // create object of class singlyList
        SinglyLList list = new SinglyLList();
 
        // insert elements of singly linked list
        // at beginning
        list.InsertAtStart(3);
        list.InsertAtStart(2);
        list.InsertAtStart(1);
 
        // print linked list elements
        list.Display();
 
        // insert element at the end of list
 
        list.InsertAtLast(1);
        Console.WriteLine("\nafter inserting node at the end\n ");
 
        // print linked list elements
        list.Display();
 
        // delete an element at the given position
        list.DeleteAtPos(1);
 
        // delete starting element
        list.DeleteAtStart();
 
        // delete last element
        list.DeleteAtLast();
 
        Console.WriteLine("\nafter deleting node: second, first and last\n ");
 
        // print linked list elements
        list.Display();
    }
}
 
// This code has been contributed by 29AjayKumar

Javascript




<script>
 
// JavaScript program to implement
// singly linked list
 
     class Node {
            constructor(val) {
                this.data = val;
                this.next = null;
            }
        }
 
    // create reference variable of Node
    var head;
 
    // function to insert a node
    // at the beginning of the list
    function InsertAtStart(data) {
        // create a node
    var new_node = new Node(data);
 
        new_node.next = head;
        head = new_node;
    }
 
    // function to insert node
    // at the end of the list
    function InsertAtLast(data) {
 
     var new_node = new Node(data);
        if (head == null) {
            head = new_node;
            return;
        }
 
        new_node.next = null;
 
        var last = head;
        while (last.next != null) {
            last = last.next;
        }
 
        last.next = new_node;
    }
 
    // function to delete a node
    // at the beginning of the list
    function DeleteAtStart() {
        if (head == null) {
            document.write("List is empty");
            return;
        }
        head = head.next;
    }
 
    // function to delete a node at
    // a given position in the list
    function DeleteAtPos(pos) {
        var position = 0;
        if (pos > Count() || pos < 0) {
             
        }
        var temp = head;
        while (position != pos - 1) {
            temp = temp.next;
            position++;
        }
        temp.next = temp.next.next;
    }
 
    // function to delete a node
    // from the end of the list
    function DeleteAtLast() {
     var deletenode = head;
        while (deletenode.next != null &&
        deletenode.next.next != null) {
            deletenode = deletenode.next;
        }
        deletenode.next = null;
    }
 
    // function to display all the nodes of the list
    function Display() {
    var disp = head;
        while (disp != null) {
            document.write(disp.data + "->");
            disp = disp.next;
        }
    }
 
    // function to return the total nodes in the list
    function Count() {
        var elements = 0;
        var count = head;
        while (count != null) {
            count = count.next;
            elements++;
        }
        return elements;
    }
 
 
  
 
    // Driver code
        // create object of class singlyList
         
 
        // insert elements of singly linked list
        // at beginning
        InsertAtStart(3);
        InsertAtStart(2);
        InsertAtStart(1);
 
        // print linked list elements
        Display();
 
        // insert element at the end of list
 
        InsertAtLast(1);
        document.write(
        "<br/>after inserting node at the end<br/><br/> "
        );
 
        // print linked list elements
        Display();
 
        // delete an element at the given position
        DeleteAtPos(1);
 
        // delete starting element
        DeleteAtStart();
 
        // delete last element
        DeleteAtLast();
 
        document.write(
        "<br/>after deleting node: second, first and last<br/>"
        );
 
        // print linked list elements
        Display();
 
// This code is contributed by todaysgaurav
 
</script>
Output: 
1->2->3->
after inserting node at the end
 
1->2->3->1->
after deleting node: second, first and last
 
3->

 

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