C# :: Proper Way For Class B To Use Class A?

Nov 18, 2014

Let's say that I have Class A. I then have Class B that is different. It is now time to add to Class B and I want to use a lot of the methods that are contained in Class A.

How should I go about tying Class A to Class B? I'm not thinking about Inheritance because Class B is not really an extension of Class A. But for the future, if myself or anyone else wants to use Class B, how would it make it apparent that Class A must be included other than the fact that I will see compiler errors all over?

View 7 Replies


ADVERTISEMENT

C++ :: Proper Way To Get Info Of One Class Into Another Class

Jan 27, 2015

I am trying to setup my game. first I have my main.cpp which just creates

Game game;
game.run();

I also have my Player class but having trouble accessing the player information from the game class. how can I make it so that my game class has access to player class? or any other class for that matter as my game class will be running everything.

View 3 Replies View Related

C++ :: Proper Way Of Using String Array Inside A Class

Jul 23, 2014

class myclass{
string myarray[5];
myarray[0] = "one"; myarray[1] = "two"; myarray[2] = "three"; myarray[3] = "four";
myarray[4] = "five";
};

this works in main function but doesn't work in the class;

1. Why this methods doesn't work inside class but works in main function?
2. What is the proper way of using string array inside a class?

View 4 Replies View Related

C++ :: Template Class Instance - Proper Datatype

Oct 20, 2012

I have a class that is a template, I have to declare it in my main but i want the user to choose what type of data they will use in the class, I cant just declare myclass my, i have to use myclass<int> my, how can I change so user can select the proper datatype to use in the class.

View 5 Replies View Related

C++ :: Display Fraction In Proper From Based On 2 Arguments Passed To Class Member Function

Mar 15, 2015

We're assigned a project working with classes and fractions. My goal is to display a fraction in proper from based on 2 arguments passed to a class member function proper();

My strategy was to utilize the greatest common factor between the 2 arguements, then divide both the numerator and denominator by that number and then it would display.

The program actually runs, but only seems to divide the numerator and not the denominator. This in return makes my other class member functions have incorrect comparisons and sums.

Code:
#include<iostream>
#include<conio.h>
class Fraction {
friend void compare(Fraction a, Fraction b);
friend void sum(Fraction a, Fraction b);

[Code] ....

View 14 Replies View Related

C++ :: Instance Of Class A Vs Class B Derived From Class A

Jul 3, 2014

There are two ways to access the members of class A inside class B:

1) Making an instance of class A in class B
2) Deriving class B from class A

So what is the basic difference in both ways as we can do same kind of work with both ways?

View 1 Replies View Related

C++ :: How To Get Object Of Original Class From Function Of Other Class Where Other Class Object Is Member Of Original Class

Jan 21, 2013

The case is like

class B{
public:
somedata;
somefunction();
}
class A{
public:
data;
function();
}

in somefunction i want a pointer to current object of class A m new to c++

View 2 Replies View Related

C++ :: Calling Derived Class Functions In A Function With Parameter Of Base Class

Mar 30, 2013

Say I have 3 classes:

class Player {
public:
virtual func1();

[code]....

Say in my main class, I have a function fight(Player p1, Player p2) and I would like to do something like this in the fight function, given that p1 is the human and p2 is the computer:

//function fight()
fight(Player p1, Player p2) {
p1.func2();
}
//using function fight()
fight(human, computer);

When I compile the program, I got this: error: ‘class Player’ has no member named 'func2()' What can I do to allow p1 to call func2 inside fight()? I'm not allowed to use pointers as the parameter for fight() and have to use the signature fight(Player p1, Player p2).

View 6 Replies View Related

C++ :: Size Of Derived Class With Overriding Virtual Functions From Base Class?

Jan 21, 2014

The compiler creates virtual table for the base class and also for the derived class whether we override it or not.

That means each class has separate virtual table. when we get the size of the each class with out any data members... the size of base is -- 4 bytes(64 bit) and the size of derived is -- 1

The size of base class 4 is correct since it creates the virtual pointer internally and its size is member data + virtual pointer, but it in this case I have included any data members so it has given 4 byts.

But why in case of derived is 1 byte, since it the derived class has overridden the virtual function from base, this will also contains the virtual pointer which will be pointing to derived class Vtable, it the size of the class suppose to be 4 instead of 1 byte.

#include<iostream>
class A{
public:

[Code].....

View 1 Replies View Related

C++ :: Transfer Values Set In Privates Of Base Class By Object Of One Derived Class To Another

Apr 26, 2014

I have my main.cpp like this:

#include <iostream>
#include "curve1.h"
#include "curve2.h"
using namespace std;
int main() {
Curve1 curve1Obj;
Curve2 curve2Obj;

[Code]...

Base class Score has two derived classes Curve1 and Curve2. There are two curve() functions, one is in Curve1 and other in Curve2 classes. getSize() returns the value of iSize.

My base class header score.h looks like this:

#ifndef SCORE_H
#define SCORE_H
class Score {
private:
int *ipScore;
float fAverage;
int iSize;

[Code]...

You can see that I have used curve1Obj to enter scores, calculate average and output. So if I call getSize() function with cuve1Obj, it gives the right size that I took from user in enterScores() function. Also the result is same if I call getSize() in score.cpp definition file in any of the functions (obviously).
.....

The problem is when I call curve() function of Curve2 class in main (line 23) with the object curve2Obj, it creates a new set of ipScore, fAverage and iSize (i think?) with garbage values. So when I call getSize() in curve() definition in curve2.cpp, it outputs the garbage. .....

How can I cause it to return the old values that are set in curve1.cpp?

Here is my curve2.cpp

#include <iostream>
#include "curve2.h"
using namespace std;
void Curve2::curve() {
cout << "getSize() returns: " << getSize() << endl; // out comes the garbage
}

Can I use a function to simply put values from old to new variables? If yes then how?

View 3 Replies View Related

C++ :: How To Initialize Static Member Of Class With Template And Type Of Nested Class

Oct 7, 2014

How to initialize a static member of a class with template, which type is related to a nested class?

This code works (without nested class):

#include<iostream>
using namespace std;
struct B{
B(){cout<<"here"<<endl;}
};
template<typename Z>

[Code] ,....

View 1 Replies View Related

Visual C++ :: Reach Top Class Inherits From Goal Class - Linker Error

Dec 10, 2012

Linker error.

First off the error

Code:
Error1error LNK2019: unresolved external symbol "public: __thiscall ReachTop<class Character>::ReachTop<class Character>(class Character *)" (??0?$ReachTop@VCharacter@@@@QAE@PAVCharacter@@@Z) referenced in function "void __cdecl `dynamic initializer for 'gReachTop''(void)" (??__EgReachTop@@YAXXZ)Main.objDecisionTest

Reach Top class inherits from Goal Class

Goal Class

Code:
#ifndef _GOAL_H
#define _GOAL_H
#include "Action.h"
#include <list>
template <class T>
class Goal

[Code] ....

Code to create

Code:
Character* gCharacter = new Character(1, gWorld);
Goal<Character>* gReachTop = new ReachTop<Character>(gCharacter);

I can provide the character class and its inheritance aswell if you like.

View 4 Replies View Related

C++ :: Deleting Array Of Derived Class Objects Through Base Class Pointer

Mar 21, 2015

In this book, item 3 is about never treat arrays polymorphically. In the latter part of this item, the author talks about the result of deleting an array of derived class objects through a base class pointer is undefined. What does it mean? I have an example here,

Code:
class B
{
public:
B():_y(1){}
virtual ~B() {
cout<<"~B()"<<endl;

[Code] ....

This sample code does exactly what I want. So does the author mean the way I did is undefined?

View 1 Replies View Related

C++ :: Creating Array Of Pointers To Base Class To Point To Derived Class Objects Dynamically

Jan 16, 2013

Please consider the following code :

#include <iostream>
using namespace std;
class superclass;
class subclass1;
class subclass2;

[Code] ....

As you can see I want to create a dynamically allocated storage of references to a parent class each of which can then point to a child class, how ever I do not know how to extract the child class out again from that array so i may access its variable b.

View 2 Replies View Related

C++ :: Initializing Inner-objects Of Base Class From Driven-class Constructor

Jan 6, 2015

Let's say I have a Car object , and it contains inner Engine object.

Code:
struct Car{
Engine mEngine;
};

In order to initialize the engine object NOT by the default constructor (if it has any) , we use initialization semantics:

Code:
Car::Car:
mEngin(arg1,arg2,...)
{
other stuff here
}

Now it gets tricky: Let's say a Car objects has 10 inner objects, each object has about 5 variables in it . Car is a base class for , e.g. , Toyota class. you don't want the Car class to have a constructor with 50 arguments. Can the inner objects of Car be initialized from the base class , e.g. Toyota?

Code:
class Toyota:
Car(...),
mEngine(...),
mGear(..)
{
...
};

The other options are:
1) like said , create a Car constructor which gets 50 arguments, then initialize Car as whole from Toyota - the code becomes less readable and less intuitive
2) Car constructor which get built-objects as arguments and initialize the inner objects with copy constructor . the code gets more readable but then you create many excess objects .

View 5 Replies View Related

C++ :: Derived Class Not Overwriting Base Class Function - Using Vectors

Feb 4, 2014

So I have a base class, lets call it base. In base I have a virtual function called update(), update just couts "base" then I have a class derived from base called derived;

it has a function called update(), update just couts "derived" then I create a vector called Vec it's initialised like this:

std::vector<base> Vec;

then I add an element into it like this

Derived DerElement;
Vec.push_back(DerElement);

then when I type:

for (int i=0; i<Vec.size(); i++) {
Vec.at(i).Update();
}

It outputs:

Derived DerElement2;
DerElement2.Update();

and it outputs this:

#include <iostream>
#include <vector>
class Base {
public:
virtual void Update() {

[Code] .....

and this is it's output:

Base
Derived
Press any key to continue . . .

View 1 Replies View Related

C++ :: Friendship From Derived Class Method To Base Class Members

Jul 15, 2014

I would like to know if there's a way to make a method from a derived class a friend of its base class. Something like:

class Derived;
class Base {
int i, j;
friend void Derived::f();
protected:
Base();

[Code] ......

View 3 Replies View Related

C++ :: Variable Belonging To Base Class - Tell Compiler Consider This To Be Derived Class?

Oct 12, 2013

I have an example where I have a variable belonging to a base class, but I would like to tell the compiler that it actually belongs to a derived class. How can I do this?

// base class: R0
// derived class: R1
// see function SetR1 for the problem
class R0 {
public:
int a;

[Code] .....

View 5 Replies View Related

C++ :: Define A Class That Only Inherits From Parent Class And Takes One Argument

Jan 5, 2015

In the project I'm currently working on I define a class that only inherits from a parent class and takes one argument.

Does this class need to be defined in the header or source file? I read different answers around the internet.

Or is it better to always split definition and logica, even for something like an operator?

View 1 Replies View Related

C++ :: Using Member Function Of A Class In Another Class And Relate It To Object In Int Main

Aug 21, 2013

I am writing a program which is using SDL library. I have two different classes which one of them is Timer Class and the other is EventHandling Class.

I need to use some member functions and variables of Timer in some Eventhandling Class member functions, Although I want to define an object of Timer in int main {} and relate it to its member function that has been used in Eventhandling member function in order that it becomes easier to handle it, I mean that I want to have for example two objects of timer and two objects of Eventhandling class for two different users.

I do not know how to relate an object of a class from int main{} to its member function which is being used in another class member function.

Lets have it as a sample code:

class Timer {
private:
int x;

public:
Timer();
get_X();
start_X();

[Code] ....

View 4 Replies View Related

C++ :: Can Base Class Call Overridden Function From Derived Class?

Aug 28, 2013

I just wondering if a base class can call the overridden function from a Derived class?

Here's an example:

//Base Class H
class BaseClass {
public:
BaseClass();
virtual ~BaseClass();
virtual void functionA();

[Code] ....

So basically, when I am creating a new object of Derived class, it will initialize BaseClass and the BaseClass will call functionA but I want it to call the function overridden by Derived class.

I know that if I call newObj->functionA it will call the overridden function. Right now I want the base class to call the overridden function "this->functionA(); in BaseClass" during its initialization. Is it possible to do that?

View 9 Replies View Related

C++ :: Delegate Class - Support Void Class Function With No Parameters

Jun 22, 2013

I'm trying to write a simple Delegate class with a Bind() and Invoke() function. For now it only needs to support a void class function with no parameters. I've searched around and found quite a few exmaples, though, those class are heavily templated and I lose track trying to simplify it.

So far my code is following:

Code:
#include <windows.h>
class Test {
public:
void DoSomething() {
MessageBox(NULL, L"Test::DoSomething!", NULL, 0);

[Code] ....

The part I am having difficulty with is assigning &Test::DoSomething to the m_Callback variable.

&tObject::DoSomething works, yet _Callback which I pass &Test::DoSomething to does not work.

Also, why does the following line work:

Code:
m_Callback = &Wrapper<tObject, &tObject::DoSomething>;

When wrapper is like:

Code:
template<class tObject, void (tObject::*Func)()>
void Wrapper(void* Object)

Should it not be Wrapper<class-typename, parameter-1>(parameter-2) // This currently creates an error

View 2 Replies View Related

C++ :: Class Function That Uses Instance Of Its Child Class As Argument

Mar 1, 2013

I am facing a real-life problem, it can be simplified as below:

#include <iostream>
using namespace std;
class B;
class A {
public:
void f1(A a) {}
void f2(B b) {}

[Code]...

There is no problem at all with the f1(), it compiles and executes without any problem. But f2() gives compilation error. How to solve this?

The error message is: error: 'b' has incomplete type This is just to define the function f2() in a class, that uses an instance of its child class as one of its arguments.

View 11 Replies View Related

C++ :: How To Call Function From Derived Class In Base Class

Dec 24, 2013

Basically, I have a base class called MainShop and it has 3 derived classes which are SwordShop, SpellBookShop and BowShop. I want the base class to be able to call a function from one of the derived classes but no matter what i do, it doesn't seem to work!

Here is my code:

#include "MainShop.h"
//BaseClass cpp
void MainShop::EnterShop(Hero& hero)

[Code]....

I have two other derived classes, but its basically the same concept. I have a function in one of the derived classes and i would like to call it from the base class. This is one my derived classes:

//SwordShop derived cpp
#include "SwordShop.h"
void SwordShop::soldierShop(Hero& hero)
{
/* some code here*/
}

View 4 Replies View Related

C++ :: Exchange Array Between Derived Class And Base Class?

Apr 8, 2014

Base class has an array, whose size is controlled by the derived class.

I can't use the STL and use a 2003 compiler, so things like std::vector and std::array are out. I also can't use dynamic memory allocation.

So I thought of a few options:

1.
template <int N> class myBaseClass { ... int array[N]; ... }

then class MyClass: public myBaseClass<8> ... etc ...

2.
have a int **array in the base and assign in the derived class.

3.
give the base some virtual methods such as int *getArray or even int &getInt for more safety.

View 6 Replies View Related

C++ :: Cannot Access Private Member Declared In One Class But Can In Another Class

Sep 4, 2014

So I have an ImageManager class, Board class, and Box class. In Board.h I can declare ImageManager imgr; and in Board's constructor I can use imgr and its functions and such. However, in Box.h when I try and declare ImageManager imgr; I get the error "cannot access member declared in class ImageManager". Both declarations are under private, and exactly the same, but one doesn't work. Also, is there a way to only have one instance of ImageManager?

View 19 Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved