//stackx.cpp
//methods for class Stack implemented using array
//exception handling is used to deal with error conditions

#include <iostream.h>
#include <math.h>
#include "stackx.h"

#define  BOS  -1

Stack::Stack(int sz) {

	if (sz<0)
		size = abs(sz);
	else
	  	size = sz;
	val = new Type[size];
	if (!val)
		throw "memory allocation error";
	top = BOS;
}


void Stack::push(Type x) {
	if (isfull())
		throw size;
	val[++top] = x;
}


Type Stack::pop() {
	if (isempty())
		throw " stack underflow";
	return val[top--];
}


int Stack::isempty() {
	return top == BOS;
}


int Stack::isfull() {
	return top == size-1;
}

void Stack::print() {
	int i;

	for (i = top; i >= 0; i--)
		cout<<val[i]<<' ';
	cout<<endl;
}

Stack::~Stack() { 
	delete [] val;
}