#include "mydefs2.h"
#include <assert.h>

// Linked list implementation of stacks.

int_stack :: node* int_stack::new_node(int d, node* n)
{
	node* t = new node;
	assert( t );
	t -> data = d;
	t -> next = n;
	return( t );
}

void int_stack :: init(int nitems = 100)
{
	top = 0;
}
void int_stack :: push(int x)
{
	top = new_node(x, top);
}
int int_stack :: pop()
{
	assert( !isempty() );
	int t = top -> data;
	node *oldtop = top;
	top = top -> next;
	delete oldtop;
	return t;
}
boolean int_stack :: isempty()
{
	return( top == 0 );
}
boolean int_stack :: isfull()
{
	return( 0 );
}