[inheritance] Forum Topics

Hi All, i am curious to know how to set the value (value=10) through B's constructor in below programme. below is example of multiple inheritance. As construction always happens from right to left so it always call the 'C' class's constructor and set the value 20 but as per my …

I have a Task class (superclass) which inherited PracticeTest class(childclass). I'd faced question regarding my pass year question. In fact, we are allowed to declared like this Task aTask = new PracticeTest(); But i wonder why we are doing this way? Thanks for advance explanation.

Is it possible to let an overridden method from a base class to return the type of the derived class? What I mean is: namespace test //with some "pseudo" code { class Base<T> { //fields ... //properties ... // ... public virtual Base<T> BaseMethod() { //return new Base<T>; } // …

Hi guys, I would like to discuss my design with one query. below is the code snippet. It is clear from below code snippet that class pd is privately derived from AbstractClass as both are different classes and there is no relation between them.Now in my class pd i need …

//Hi all just switching from c++ to c#.Can anyone help,with the question i have: //this is a peace of code from c++ banking aplication int ShowMenu(void); void AddAccount(vector<CAccount*>& list); void DisplayAccount (vector<CAccount*>& list); void Lodgement (vector<CAccount*>& list); void Withdroawal (vector<CAccount*>& list); void InterestRate (vector<CAccount*>& list); CAccount* findAccount (vector<CAccount*>string ); bool …

One of my students make me a question (which answer i know) but I think could be instructive to formulate the same question here so many people can learn about it. The question is: How to implement a copy assignment into a Derived class? Consider the following class A: class …

Hey everybody, As of this moment i'm trying to work out how to approach a state design. I've come across Source Makers' site [http://sourcemaking.com/design_patterns/state/cpp/1](http://sourcemaking.com/design_patterns/state/cpp/1) and am testing out the example. The program works fine when it's all in 1 file, although i had to change some stuff in main, but …

I'm trying to create a program that passes arguments of size of three shapes, a circle, a triangle, and a rectangle. I got those but everytime I run the code it displays the arguments as 0 instead of giving me the shape dimension. Here is the code. using System; class …

I have two classes A Dog class whose constructor does not accept arguments, `public class Dog<pet> extends Animal<pet>{}` whose constructor does not accept any arguments and `public class Animal<pet>{}` whose constructor accepts one argument public class Dog<pet> extends Animal<pet>{ public Dog(){ super(/*what should go here?*/); //Constructor accepts no arguments } …

This started out as `I love PHP traits! I'm going to use them everywhere! ^_^` and now it has turned into a `Thought Exercise / Learning Experience >_<`. Consider the following example: trait TheErrorOfYourWays{ public function booboo(){ echo 'You had a booboo :('; } } trait SpectacularStuff1 { use TheErrorOfYourWays; …

Hello, I am working on an event driven library and am having one minor problem. Basically I have two ways to get what I want done. Method 1: Smart pointers and factory functions #include <iostream> #include <vector> #include <memory> using namespace std; class Object { public: virtual int getInt(){return 0;} …

#ifndef BASE_H #define BASE_H class Base { public: int m_nValue; Base(int nValue=0) : m_nValue(nValue) { std::cout << "Base" << std::endl; } }; #endif #ifndef DERIVED_H #define DERIVED_H #include "Base.h" class Derived: public Base { public: double m_dValue; Derived(double dValue=0.0) : m_dValue(dValue) { std::cout << "derived se" << std::endl; } friend …

I'm trying to create a list stack that implements some interface called SomeList The list stack should only use stack with no links. the itnerface has a number of methods that I would like to implement. So for SomeList I have something like public interface SomeList<T>{public void plus(T something);public E …

Hey guys, slightly less noob programmer here for a some more help, This week in class we were assigned to create a phonebook with a couple functions to manipulate it, but it seems I am having a couple problems. It seems to me that I have most of the program …

Hi Guys, I am trying to teach myself templates and I keep getting lost in all these compilation errors. Here is the latest // This is the interface for the base class template<class V, class I =int> class Array{ private: vector<V> myStore; public: Array(); Array(I size); Array(I size, V value); …

Hey guys, noob programmer here. Over the last week or so we've been learning about classes and inheritance in my latest progamming class. I've recieved a variation of the ever so popular poker program and am having some problems putting it all together. I haven't had the opportunity to test …

I have the following structure: CObject { protected: char *mName; public: CObject(char *n) { mName=strdup(n); } }; CVector:public CObject { char *mValues[50]; int mElements; public: CVector(char *n):CObject(n) {} }; CMatrix:public CObject { char *mValues[50][50]; int mLines; int mColumns; public: CMatrix(char *n):CObject(n) {} }; My main function: int main() { pV=new …

Hello, I have a chain of inherited classes like this: class A { protected: int a; public: int getA(){return a;} }; class B:public A { protected: int b; public: int getB(){return b;} }; Based on that you can see that the public can only read the values in those classes, …

Traceback (most recent call last): File "C:/Users/James/Desktop/hugevar.py", line 2, in <module> class var(tempfile.TemporaryFile): TypeError: Error when calling the metaclass bases function() argument 1 must be code, not str Why does this happen and how can I fix it?

So basically im creating this python adventure text game. And so far its good. But i have this problem with class instances(Is that the right term?) Say for example i have this class, class monster(object): def __init__(self,health,attack): self.damage = damage self.health = health So then I create a class object(again, …

is it necessary to include base class in the header and or .cpp file of derived class?

I am having a problem to understand how class inhertance works in Java.. Now I want to get information from a class to another and let's say we have class A and class B class A contains a string an int and a byte class B contains a String and …

Hello all, I have not tested the code I'm posting here to see if it compiles, but I have an issue in a large codebase and I believe that this should be the simplest program to demonstrate the issue; class base { public: shared_ptr<base> clone()=0; }; typedef shared_ptr<base> baseptr; class …

Hello, I am working on a homework problem that has to do with inheritance, I thought that as long as the class interface and implementation files for the base classes the derived would work with the include statement: #include "salariedemployee.h" and the line class administrator : public salaried employee. I …

<? super Animal> means animal or it's superclass only. Then why inside the method it's allowing to add Dog object even though it's a subclass of Animal? This program compiles and runs! import java.util.*; class Cat {} class Animal{Animal() {System.out.println("Animal constructor");}} class Dog extends Animal{Dog() {System.out.println("Dog constructor");}} public class GenericDemo5 …

class Sample1 { Sample1() {System.out.println("Sample1 const"); } void doStuff(){System.out.println("sample1 dostuff"); } } class Sample2 extends Sample1 { Sample2() {System.out.println("Sample2 const"); } } public class Sample3 extends Sample2 { Sample3() {System.out.println("Sample3 const"); } public static void main(String r[]) { new Sample3().go(); } void go() { super.doStuff(); } } The output is: …

import java.io.*; public class Mac extends Laptop { public static void main(String r[]) { new Mac().crunch(); } //insert code here } class Laptop { void crunch() throws IOException { } } The question is simple. Insert a code that will make the program compile. Answers are: `void crunch()` or `void …

int [] ia1 = {1,2,3}; int [][] ia2; Object o = ia1; ia2 = new int [3][3]; ia2[0] = (int[])o; ia2[0][0] = (int[])o; Answer is "Compilation fails in last line" Explanation: Arrays are objects, and that each array dimension is a separate type. So, for instance, ia2 is of type …

import java.util.*; class SampleA { } class SampleB extends SampleA{ } class SampleC extends SampleA{ } class VectorDemo { public static void main(String r[]) { Vector<SampleA> v = new Vector<SampleA>(); v.add(new SampleB()); v.add(new SampleC()); SampleC rect = v.get(2); } } The output says "Incompatible types. Found SampleA, required SampleC. SampleC …

Lets say I have a class A and I also have classes B and C that inherit from class A class A { virtual void foo()=0; //stuff } class B : class A { void foo(); //more specific stuff } class C : class A { void foo(); //more specific …