#include<stdio.h>
#include<stdlib.h>

struct Node
{
	int data;
	struct Node* next;
};

// Two glboal variables to store address of front and rear nodes.
struct Node* front = NULL;
struct Node* rear = NULL;

// To Enqueue an integer
void Enqueue(int x)
{
	struct Node* temp = (struct Node*)malloc(sizeof(struct Node));

	temp->data =x;
	temp->next = NULL;

	if (front == NULL && rear == NULL)
	{
		front = rear = temp;
		return;
	}

	rear->next = temp;
	rear = temp;
}

// To Dequeue an integer.
void Dequeue()
{
	struct Node* temp = front;

	if (front == NULL)
	{
		printf("Queue is Empty\n");
		return;
	}

	if (front == rear)
	{
		front = rear = NULL;
	}
	else
	{
		front = front->next;
	}

	free(temp);
}

void Print()
{
	struct Node* temp = front;

	while (temp != NULL)
	{
		printf("%d ",temp->data);
		temp = temp->next;
	}

	printf("\n");
}

int main()
{
  // Drive code to test the implementation.
	// Printing elements in Queue after each Enqueue or Dequeue
	Enqueue(2); Print();
	Enqueue(4); Print();
	Enqueue(6); Print();
	Dequeue();  Print();
	Enqueue(8); Print();
}