//      queue.cpp
//      
//	Source: class notes w/ additions

#include <iostream>
using namespace std;
class Queue
{
     private:
         struct Node
         {
               Node (int data, Node* next) :
                   mydata(data), mynext(next) {}
               int mydata;
               Node *mynext;
         };
     public:
         Queue() : count(0), myfront(NULL), myback(NULL){} // added count initializer
         ~Queue();
         int front() const;
         int back() const;
         bool is_empty() const;
         void enqueue(const int);
         void dequeue();
         bool Filter(int);
         void callFilter(); //Calls the filter function
         
         // added (begin)
         int front_and_dequeue();
         int count;
         // added (end)
         
     private:
          Node* myfront;
          Node* myback;
};

/* Implementation of member functions */
Queue :: ~Queue()
{
     if (myfront == NULL) return;
     for (Node *p = myfront->mynext; p; p=p->mynext)
          delete myfront;
}
int Queue :: front() const
{
     return myfront->mydata;
}
int Queue :: back () const
{
     return myback->mydata;
}
bool Queue :: is_empty () const
{
     return bool(myfront == NULL);
}
void Queue :: enqueue(const int d)
{
     Node *p=new Node(d, NULL);
     if (myback == NULL){
          myback=p;
          myfront=p;
     }
     else {
          p->mynext=myback;
          myback=p;
     }
     
     // added (begin)
     count++;
     // added (end)
     
     cout<<"Item entered into the queue: "
           <<myback->mydata<<endl;
}
void Queue :: dequeue()
{
     Node *p=myback;
     if (is_empty())
           cout << "Queue empty: Nothing to delete"<<endl;
     else {
           if (myback==myfront){
                cout<<"Item removed from queue: "
                <<myback->mydata<<endl;
                delete myback;
                myback=NULL;
                myfront=NULL;
               
           }
           while(p->mynext != myfront)
                p=p->mynext;
           int d=myfront->mydata;
           cout<<"Item removed from queue: "<<d<<endl;
           delete myfront;
           myfront=p;
     }
     count--;
}

// added (begin)
int Queue :: front_and_dequeue() {
	int retval = front();
	dequeue();
	return retval;
}
// added (end)
void Queue::callFilter()
{
	int value, Try;
	Try = 0;
	
	cout << "Please enter the value that you wish to search for(anything other than 0: ";
	cin >> value;
	
	while (Try < 10)
		if (value > 0) {
			Filter(value);
			break;
		} else {
			cout << "Please enter a new value you have " << 10-Try << " chances left: ";
			cin >> value;
			Try++;
		}
}
bool Queue::Filter(int A){
	int B, C, exit, c;
	
	c = 0;
	B = front();
	C = B; //to remeber the first value
	exit = 0;
	while(exit == 0){
   
		if (front() == A){
			dequeue();
			exit = 1;
			break;
		} else {               
			enqueue(front_and_dequeue());
			c += 1;           
		} 
	
	}

	for (int i=0; i < count - c; i++)//get back to the original front
	{           
		enqueue(front_and_dequeue());
	}
}

main() /* A test-drive for queue */
{
     Queue q;
     q.enqueue(45);
     q.enqueue(56);
     q.enqueue(32);
    
     q.enqueue(12);
     q.enqueue(89);
     q.callFilter();
     q.dequeue();
     q.dequeue();
     q.dequeue();
     q.dequeue();
     q.dequeue();
}