On Mar 31, 3:27 am, el mio uno y dos <[email protected]> wrote:
> Hello bulimic, i think that circulo is not a inner class of cilindro. I think
> that circulo is a subclass of cilindro. I send a copy of how i do it. Please
> see it and tell me if is correct.
Hello. I did not receive any copy. Anyway, we can discuss here.
Circulo inherits cilindro is odd. I think it would be more efficient
if cilindro extends circulo as it can take advantage of code re-use.
For example:
public class Circulo{
public double area(double radius){
}
public double perimetro(double radius){
}
}
public class Cilindro extends Circulo{
public double area(double radius, double height){
// Use circulo's methods to calculate cilindro's area. Then
return.
double areaCirculo=area(radius), perimetroCirculo=perimetro
(radius);
}
}
>
>
>
> > Date: Mon, 30 Mar 2009 11:53:33 -0700
> > Subject: [java programming] Re: Logic error!
> > From: [email protected]
> > To: [email protected]
>
> > On Mar 31, 1:36 am, jose luis garcia <[email protected]> wrote:
> > > *Hello everybody... I have a problem. I wrote a code for a program that
> > > have
> > > 1 superclass and 1 class extends. the code it`s follow:*
>
> > > //Programa que realiza algunos calculos mediante las caracteristicas de un
> > > cilindro
>
> > > package cilindro;
>
> > > // @author louis
>
> > > import java.util.Scanner;
>
> > > public class Cilindro {
> > > double pi = Math.PI;
>
> > > public Cilindro(){
> > > // super();
>
> > > }
>
> > > public double areaCilindro(double r, double h){
> > > double area = (2*pi*r*h) + (2*pi*r*r);
>
> > > return area;
> > > }
>
> > > public double perimetroCilindro(double r, double h){
> > > double perimetro = (4*pi*r)+(2*h);
>
> > > return perimetro;
>
> > > }
>
> > > public class Circulo extends Cilindro{
>
> > > Circulo(){
> > > super();
> > > }
>
> > > public double areaCirculo(double r){
>
> > > double area = pi*r*r;
> > > return area;
> > > }
>
> > > public double perimetroCirculo(double r){
> > > double perimetro = 2*pi*r;
>
> > > return r;
> > > }
>
> > > }
>
> > > public static void main(String[] args) {
>
> > > // Cilindro obj = null;
> > > Circulo obj1 = null;
> > I suspect the culprit is the inner class. If I remember correctly, an
> > inner class type declaration should be like:
> > Cilindro.Circulo obj1 = null;
>
> > > double radio = 0,altura = 0;
> > > Scanner input = new Scanner(System.in);
>
> > > System.out.println("Ingresa Radio: ");
> > > radio = input.nextFloat();
>
> > > /* System.out.println("Ingresa altura: ");
> > > altura = input.nextFloat();
> > > */
> > > String resultado = "Area del circulo: " +
> > > obj1.areaCirculo(radio);
>
> > > System.out.println(resultado);
>
> > > }
>
> > > }
>
> > > *Netbeans not generate any error. But at the moment that run the program
> > > and
> > > insert a float, Netbeans generate me this message:*
>
> > > run:
> > > Ingresa Radio:
> > > Exception in thread "main" java.lang.NullPointerException
> > > at cilindro.Cilindro.main(Cilindro.java:66)
> > > 2.23
> > > Java Result: 1
> > > GENERACIÓN CORRECTA (tiempo total: 3 segundos)
>
> > > *
> > > I`m sure that is a logic error... help me please. Thanks!
> > > *
>
> _________________________________________________________________
> Descubre todas las formas en que puedes estar en contacto con amigos y
> familiares.http://www.microsoft.com/windows/windowslive/default.aspx
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/javaprogrammingwithpassion?hl=en
-~----------~----~----~----~------~----~------~--~---
