[derived] Forum Topics

Hello, I'm trying to understand some things about derived classes: how to add something "extra" to existing functions in base class. My base class is "shape2D" like a rectangle, 3 functions: set values, calculate, show results. No problem here. Then I create a derived class named "shape3D". Please note the …

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 …

Hey all, I've been programming an ISBN system of sorts and I'm a little stuck (again). I want to output my linked list to a text file, so I setup the code like this: [code] void saveList(char fileName[40]) { for ( list< Publication* >::iterator it = pubList.begin(); it != pubList.end(); …

Hey all, I'm attempting to use an STL List to store a list of objects. Now I realise it's quite trivial to store a list of objects of my own definition. My real question is, how do I fill the list with objects that inherit from a base class. E.g. …

#include<iostream> using namespace std; class area { double dim1, dim2; public: void setarea(double d1, double d2) { dim1= d1; dim2 = d2; } void getdim(double &d1, double &d2) { d1 = dim1; d2 = dim2; } virtual double getarea() { cout<<"You must override this functionn"; return 0.0; } }; class …

Hi, I have a list of base types which stores multiple derived types. The following code shows a simplified setup. [CODE]#include "Base.h" #include "DerivedA.h" #include "DerivedB.h" #include <iostream> #include <list> void main() { std::list<Base*> base; std::list<Base*> *basePointer = &base; for (int i = 0; i < 10; i++) { basePointer->push_back(new …

Hello all I have a query,may be silly but i have to clear it.IT IS REGARDING THE UPCASTING.I want to "when we can invoke the methods of base class using the object of derived class.then what is the need of assigning the subclass object to base class reference." I mean …