Create Queue-Queue Using LL

Author: mmuskan22

Queue-Queue Using LL

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+Implement a Queue Data Structure specifically to store integer data using a Singly Linked List.
+The data members should be private.
+You need to implement the following public functions :
+1. Constructor:
+It initialises the data members as required.
+2. enqueue(data) :
+This function should take one argument of type integer. It enqueues the element into the queue and returns nothing.
+3. dequeue() :
+It dequeues/removes the element from the front of the queue and in turn, returns the element being dequeued or removed. In case the queue is empty, it returns -1.
+4. front() :
+It returns the element being kept at the front of the queue. In case the queue is empty, it returns -1.
+5. getSize() :
+It returns the size of the queue at any given instance of time.
+6. isEmpty() :
+It returns a boolean value indicating whether the queue is empty or not.
+Operations Performed on the Stack:
+Query-1(Denoted by an integer 1): Enqueues an integer data to the queue.
+
+Query-2(Denoted by an integer 2): Dequeues the data kept at the front of the queue and returns it to the caller.
+
+Query-3(Denoted by an integer 3): Fetches and returns the data being kept at the front of the queue but doesn't remove it, unlike the dequeue function.
+
+Query-4(Denoted by an integer 4): Returns the current size of the queue.
+
+Query-5(Denoted by an integer 5): Returns a boolean value denoting whether the queue is empty or not.
+Input Format:
+The first line contains an integer 'q' which denotes the number of queries to be run against each operation on the queue. 
+Then the test cases follow.
+
+Every 'q' lines represent an operation that needs to be performed.
+
+For the enqueue operation, the input line will contain two integers separated by a single space, representing the type of the operation in integer and the integer data being enqueued into the queue.
+
+For the rest of the operations on the queue, the input line will contain only one integer value, representing the query being performed on the queue.
+Output Format:
+For Query-1, you do not need to return anything.
+For Query-2, prints the data being dequeued from the queue.
+For Query-3, prints the data kept on the front of the queue.
+For Query-4, prints the current size of the queue.
+For Query-5, prints 'true' or 'false'(without quotes).
+
+Output for every query will be printed in a separate line.
+ Note:
+You are not required to print anything explicitly. It has already been taken care of. Just implement the functions.
+Constraints:
+1 <= q <= 10^5
+1 <= x <= 5
+-2^31 <= data <= 2^31 - 1 and data != -1
+
+Where 'q' is the total number of queries being performed on the queue, 'x' is the range for every query and data represents the integer pushed into the queue. 
+
+Time Limit: 1 second
+Sample Input 1:
+7
+1 17
+1 23
+1 11
+2
+2
+2
+2
+Sample Output 1:
+17
+23
+11
+-1
+Sample Input 2:
+3
+2
+1 10
+4
+Sample Output 2:
+-1 
+1
+
+********************************************************Code************************************************
+public class Queue {
+
+	private Node front;
+	private Node rear;
+	private int size;
+
+	public Queue() {
+		
+		front=null;
+		rear=null;
+		size=0;
+	}
+  public int getSize() { 
+		
+		return size;
+    }
+    
+  public boolean isEmpty() { 
+    	
+		return size==0;
+   }
+
+ public void enqueue(int data) {
+    	
+		Node ele= new Node(data);
+      if(front==null)
+      {
+        front=ele;
+        rear=ele;
+      }
+      else{
+        rear.next=ele;
+        rear=ele;
+      }
+      size++;
+    }
+
+
+    public int dequeue() {
+    	
+      if(front!=null)
+      {
+        int temp=front.data;
+        front=front.next;
+        size--;
+        return temp;
+      }
+      else{
+        return -1;
+      }
+    }
+
+
+    public int front() {
+  
+      if(front!=null)
+      {
+        return front.data;
+      }
+      else	
+        return -1;
+      }
+    }
+