// Queue.cpp: implementation of the CQueue class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "BFSearch.h"
#include "Queue.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CQueue::CQueue(int sz)          // Constructor
{
   // Make list array one position larger  for empty slot
    size =  sz + 1;
    rear =  0;   
	front  =  1;
    listArray = new int[size];
}

CQueue::~CQueue()
{
	delete  []  listArray;
}

void CQueue::clear()  
{  
	front = rear;  
}

bool CQueue::enqueue(int &it)
{
	if  (((rear+2)  % size) ==   front)  
		return false;   // Full
	rear =  (rear+1)  %  size;  //  Circular increment
	listArray[rear]  =  it;
	return true;
}
   
bool CQueue::dequeue(int &it)  
{
       if  (length() == 0)  return false;   // Empty
       it = listArray[front];
       front =  (front+1)  % size;  // Circular increment
       return true;
}

bool  CQueue::frontValue(int &it) 
{
       if  (length() == 0)  
		   return false;   // Empty
       it =  listArray[front];
       return  true;
}

int CQueue::length()
{ 
	return  ((rear+size)  -  front + 1)  % size;  
}