Circular Queue

circularQueue.cpp

#include<iostream>
using namespace std;
#define MAX_SIZE 11
// Creating a class named Queue.
class Queue
{
private:
	int A[MAX_SIZE];
	int front, rear;
public:
	Queue(){
		front = -1;
		rear = -1;
	}

	// To check wheter Queue is empty or not
	bool IsEmpty(){
		return (front == -1 && rear == -1);
	}

	// To check whether Queue is full or not
	bool IsFull(){
		return (rear+1)%MAX_SIZE == front ? true : false;
	}

	// Inserts an element in queue at rear end
	void Enqueue(int x){
		cout<<"Enqueuing "<<x<<" \n";
		if(IsFull()){
			cout<<"Error: Queue is Full\n";
			return;
		}
		if (IsEmpty())
			front = rear = 0;
		else
		    rear = (rear+1)%MAX_SIZE;
		A[rear] = x;
	}

	// Removes an element in Queue from front end.
	void Dequeue()
	{
		cout<<"Dequeuing \n";
		if(IsEmpty()){
			cout<<"Error: Queue is Empty\n";
			return;
		}
		else if(front == rear ){
			rear = front = -1;
		}
		else{
			front = (front+1)%MAX_SIZE;
		}
	}

	int Front()
	{
		if(front == -1){
			cout<<"Error: cannot return front from empty queue\n";
			return -1;
		}
		return A[front];
	}

	void Print()
	{
		// Finding number of elements in queue
		int count = (rear+MAX_SIZE-front)%MAX_SIZE + 1;
		cout<<"Queue       : ";
		for(int i = 0; i <count; i++)
		{
			int index = (front+i) % MAX_SIZE; // Index of element while travesing circularly from front
			cout<<A[index]<<" ";
		}
		cout<<"\n\n";
	}
};
int main()
{
   Queue Q;
   Q.Enqueue(2);  Q.Print();
   Q.Enqueue(4);  Q.Print();
   Q.Enqueue(6);  Q.Print();
   Q.Dequeue();	  Q.Print();
   Q.Enqueue(8);  Q.Print();
}