Bulimic, i dont knows if is right to calculate cilindro`s and circulo´s area and perimetro. I dont renember how to do it.... i must take a book for renember...jejjejej
> Date: Mon, 30 Mar 2009 14:32:33 -0700 > Subject: [java programming] Re: Logic error! > From: [email protected] > To: [email protected] > > > 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 > > > _________________________________________________________________ Llévate Messenger en el móvil a todas partes ¡Conéctate! http://www.microsoft.com/spain/windowsmobile/messenger/default.mspx --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
