Copia Pilha

public LinkStack copia_pilha(LinkStack P){
    LinkStack aux = new LinkStack();
    LinkStack copy = new LinkStack();

    while(!P.isEmpty())
        aux.push(p.pop());

    while(!aux.isEmpty()){
        int data = aux.pop();
        p.push(data);
        copy.push(data);
    }

    return copy;
}