programming-examples/c++/Others/QueueAr.cpp - Implementation for queue - array version.cpp
2019-11-15 12:59:38 +01:00

97 lines
2.5 KiB
C++

QueueAr.cpp - Implementation for queue - array version
#include "QueueAr.h"
/**
* Construct the queue.
*/
template <class Object>
Queue<Object>::Queue( int capacity ) : theArray( capacity )
{
makeEmpty( );
}
/**
* Test if the queue is logically empty.
* Return true if empty, false otherwise.
*/
template <class Object>
bool Queue<Object>::isEmpty( ) const
{
return currentSize == 0;
}
/**
* Test if the queue is logically full.
* Return true if full, false otherwise.
*/
template <class Object>
bool Queue<Object>::isFull( ) const
{
return currentSize == theArray.size( );
}
/**
* Make the queue logically empty.
*/
template <class Object>
void Queue<Object>::makeEmpty( )
{
currentSize = 0;
front = 0;
back = -1;
}
/**
* Get the least recently inserted item in the queue.
* Return the least recently inserted item in the queue
* or throw Underflow if empty.
*/
template <class Object>
const Object & Queue<Object>::getFront( ) const
{
if( isEmpty( ) )
throw Underflow( );
return theArray[ front ];
}
/**
* Return and remove the least recently inserted item from the queue.
* Throw Underflow if empty.
*/
template <class Object>
Object Queue<Object>::dequeue( )
{
if( isEmpty( ) )
throw Underflow( );
currentSize--;
Object frontItem = theArray[ front ];
increment( front );
return frontItem;
}
/**
* Insert x into the queue.
* Throw Overflow if queue is full
*/
template <class Object>
void Queue<Object>::enqueue( const Object & x )
{
if( isFull( ) )
throw Overflow( );
increment( back );
theArray[ back ] = x;
currentSize++;
}
/**
* Internal method to increment x with wraparound.
*/
template <class Object>
void Queue<Object>::increment( int & x )
{
if( ++x == theArray.size( ) )
x = 0;
}