#include "StackAr1.h"

/**
 * Construct the stack.
 */
template <class Object>
Stack<Object>::Stack( ) : theArray( 1 )
{
    topOfStack = -1;
}

/**
 * Test if the stack is logically empty.
 * Return true if empty, false, otherwise.
 */
template <class Object>
bool Stack<Object>::isEmpty( ) const
{
    return topOfStack == -1;
}

/**
 * Make the stack logically empty.
 */
template <class Object>
void Stack<Object>::makeEmpty( )
{
    topOfStack = -1;
}

/**
 * Get the most recently inserted item in the stack.
 * Does not alter the stack.
 * Return the most recently inserted item in the stack.
 * Throw Underflow if stack is already empty.
 */
template <class Object>
const Object & Stack<Object>::top( ) const
{
    if( isEmpty( ) )
        throw UnderflowException( );
    return theArray[ topOfStack ];
}

/**
 * Remove the most recently inserted item from the stack.
 * Throw Underflow if stack is already empty.
 */
template <class Object>
void Stack<Object>::pop( )
{
    if( isEmpty( ) )
        throw UnderflowException( );
    topOfStack--;
}

/**
 * Insert x into the stack.
 */
template <class Object>
void Stack<Object>::push( const Object & x )
{
    if( topOfStack == theArray.size( ) - 1 )
        theArray.resize( theArray.size( ) * 2 + 1 );
    theArray[ ++topOfStack ] = x;
}

/**
 * Return and remove most recently inserted item from the stack.
 * Return most recently inserted item.
 * Throw Underflow if stack is already empty.
 */
template <class Object>
Object Stack<Object>::topAndPop( )
{
    if( isEmpty( ) )
        throw UnderflowException( );
    return theArray[ topOfStack-- ];
}