/** Evalúa, imprime y simplifica 2 + 3 * 4 y (1 * x) + 0. */
public class ExprDemo {
    public static void main(String[] args) {
        Expr e = new Add(new Num(2), new Mul(new Num(3), new Num(4)));
        IO.println(e);
        IO.println(Calc.show(e) + " = " + Calc.eval(e));

        Expr f = new Mul(new Add(new Num(2), new Num(3)), new Num(4));
        IO.println(Calc.show(f) + " = " + Calc.eval(f));

        Expr g = new Add(new Mul(new Num(1), new Num(7)), new Num(0));
        IO.println(Calc.show(g) + "  se simplifica a  " + Calc.show(Calc.simplify(g)));
    }
}