public T pop()
{
if (current != null)
{
current = current.next;
T tmp = current.value;
return(tmp);
}
else
{
throw new NullReferenceException();
}
}
public void push(T elem)
{
if (current == null)
{
current = new NextVal <T>()
{
value = elem, next = null
};
}
else
{
NextVal <T> temp = new NextVal <T>()
{
value = elem, next = current
};
current = temp;
}
}