//stack1.cpp
//methods for class Stack implemented using nodes

#include <iostream.h>
#include <assert.h>
#include "stack1.h"


Stack::Stack() {
	top = NULL;
}


Stack::~Stack() {
	Node *p, *q;

	p = top;
	while(p) {
		q = p;
		p = p->getnext();
		delete q;
	}
}

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

void Stack::push(Type x) {
	Node *p = new Node;
	assert(p);
	p->setinfo(x);
	p->setnext(top);
	top = p;
}

Type Stack::pop() {
	Node *p;
	Type x;

	assert(!isempty());

	p = top;
	x = p->getinfo();
	top = p->getnext();
	delete p;
	return x;

}

void Stack::print() {
	Node *p;

	p = top;
	while(p) {
		cout<<p->getinfo()<<' ';
		p = p->getnext();
	}
   cout<<endl;
}