C++ :: How To Create A Class Object Inside Another Class

Feb 20, 2015

My thought is that I would need to establish a variable for the class in the header and call the class within the .cpp file

//class A.h
B b;

Then in class A, to create the object and use a method from the object I would -

//class A.cpp
A::A(){
b();
}
int someAmethod(){
b.bmethod();
}

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C++ :: Initializing Object Of Class Inside Another Class?

Mar 7, 2014

I have a class MySeqBuildBlockModule that I am inheriting from: public SeqBuildBlock. Other than constructor and destructor, this class MySeqBuildBlockModule has a method: prep.

class MySeqBuildBlockModule: public SeqBuildBlock {
friend class SeqBuildBlockIRns;
public:
MySeqBuildBlockModule (SBBList* pSBBList0, long TI1_In, long TI2_In)// more arguements in this constructor of derived class
: SeqBuildBlock (pSBBList0)

[code]....

I would have like to intiantiate an object "myIRns_3" of a class defined in third party library

SeqBuildBlockIRns myIRns_3(pSBBList2);

and would like to access it from the prep function as:

double dEnergyAllSBBs_DK = myIRns_3.getEnergyPerRequest();

I tried to instantiate following in either private section or in constructor; but w/o any success:

SeqBuildBlockIRns myIRns_3(pSBBList2);

ERRORS encountered:

When I tried to do it inside the constructor, I get the following errors:

MySBBModule.h(113) : error C2065: 'myIRns_3' : undeclared identifier
MySBBModule.h(113) : error C2228: left of '.getEnergyPerRequest' must have class/struct/union type
MySBBModule.h(116) : error C2065: 'pSBBList' : undeclared identifier
MySBBModule.h(116) : error C2227: left of '->prepSBBAll' must point to class/struct/union

When I tried to do it in private section, I get the following errors:

MySBBModule.h(106) : error C2061: syntax error : identifier 'pSBBList2'
MySBBModule.h(113) : error C2228: left of '.getEnergyPerRequest' must have class/struct/union type
MySBBModule.h(116) : error C2065: 'pSBBList' : undeclared identifier
MySBBModule.h(116) : error C2227: left of '->prepSBBAll' must point to class/struct/union

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C++ :: Object Inside Class Becomes NULL?

Nov 18, 2013

I have built LOG4CXX lib and DLL and trying to use it in my application

Loh.h
class Log
{
public:

[Code].....

In my main I am initializing Log class object and calling Debug method to log debug message to a file.

Issue I am facing is at if(CLogger::oLogger != NULL) which is always returning oLogger as NULL.

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C/C++ :: Declare Parent Object Inside Class Constructor

Mar 24, 2014

This keeps giving me the error

ecg.h:18:11: error: field "next" has incomplete type

How do I do what I need? It does the same thing whether I use a class or a struct. This is C++ code

struct ECG_node {
double voltage;
clock_t time;
ECG_node next;

[Code] .....

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C++ :: How To Use A String To Create Class Object

Dec 24, 2014

I wanted to create a new class object and I want to name it from a string. Something like this:

string name = "Mike";
Customers name;
//to create a new object in customer class using the name string

Is there any way to do this?

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C++ :: Create 5 Instance Object Of Class Test?

Apr 27, 2014

I am new to C++. I am trying to create 5 instance object of class Test. I wonder if these two codes are the same.

Test testArray[5];
//which one is the correct way or what is the correct way?
for(i=0;i<5;i++)
{
Test testArray;
}

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C++ ::  How To Create Global Object / Instance Of A Class

Aug 25, 2013

I'm new in object oriented programming. I need creating a global object/instance of a class, that can be used by any function.

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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++

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C++ :: Make Class Created Static Inside Another Class?

Dec 17, 2013

it seems everytime i use statics in a class i come across with a porblem.

this time i wanted to make a class i created static inside another class.

MainVariables.h file
static fge::window mWinMain;

if someone ever wants to reach it
MainVariables.cpp file

fge::window MainVariables::mWinMain;
...
...
fge::window MainVariables::GetWinMain()
{
return mWinMain;
}

but when i created some other MainVariables classes at other places instead of them reaching to the same window two window is being created.

yes i know maybe there are better methods but currently i m working on polymorphism and i need some static members.

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Visual C++ :: Access Variable Inside Class From Other Class

Nov 9, 2013

I am trying to access a variable from another class through another class but it is not returning its "instance"?

Example:
Class View

Code:
...
V3D_Viewer viewer;
...
Class MainWindow

Code:
...
viewer* myView;
myView = new viewer();
...
Class Test

Code:
...
MainWindow window;
window.myView->setBackgroundColor(WHITE);
...

I am new to c++ references and pointers,

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C++ :: Call From Class Created Inside A Class

May 21, 2014

I have 2 Classes.
-> StateManager
-> Intro

The StateManager creates the Intro. I want that the Intro calls a function of the StateManager if finished. How can I achieve that?

At line 24 at the Intro class you can see what I tried.

StateManager:

#pragma once

#include "State.h"
#include "Intro.h"
class StateManager{
private:
std::vector <State*> States;

[Code] .....

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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?

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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] ....

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C++ :: Declare Template Type Object Inside Template Type Class Definition

Oct 12, 2013

Let me put it into the code snippet:

/**
This class build the singleton design pattern.
Here you have full control over construction and deconstruction of the object.
*/
template<class T>
class Singleton

[Code]....

I am getting error at the assertion points when i call to the class as follows:

osgOpenCL::Context *cxt = osgOpenCL::Singleton<osgOpenCL::Context>::getPtr();

I tried commenting assertion statements and then the debugger just exits at the point where getPtr() is called.

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C++ :: Creating One Class Object In Constructor Of Another Class

Sep 20, 2013

Suppose I have two classes A and B so how to access object of class A in constructor of B's class as a parameter.

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C++ ::  Declaring Object Of A Class In Another Class

Jul 14, 2014

Information:
I'm using Code::Blocks v12.11.
(I'm using C++/SDL2, but I think that's of no relevance)

Problem:
I create a class named "CSprite" in a "Sprite.hpp"-file. I create a "Sprite.cpp"-file, which includes the "Sprite.hpp"-file. I define the methods of the class "CSprite" in the "Sprite.cpp"-file.

When I try to create an object of "CSprite" in the class named "CPlayer" in the file "Player.hpp" I get an error message. (<-- Looks complicated I know, the code example will be more usefull than this)

Error in the build messages:
C:UsersLinoDocuments1 Data LinoFreizeit1 ProgrammierenC++ & SDL2The Running ManCPlayer.h|30|error: 'CSprite' does not name a type|
||=== Build finished: 1 errors, 0 warnings (0 minutes, 1 seconds) ===|

Code Example:

Sprite.hpp
#ifndef _SPRITE_HPP_
#define _SPRITE_HPP_
class CSprite {

[Code] .....

What did I miss? Did I include the wrong file? Or did I Forget to include the file? Why do I get the error message?

I also tried it with a pointer declaration and the "->" Operator but I got the same error message. I know I could just write a new function to load the texture in my "CPlayer"-class but this would not really answer my question.

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C++ :: Can Object Of A Class Be Assigned To Another Of Different Class?

Nov 9, 2013

I fully understand that a variable of one simple data type cannot be assigned to another of a different data type in an assignment statement, except when type-conversion(i.e. casting) is employed. For structured data types (like classes), I know that the assignment operator can be overloaded; but this only addresses objects of the same type.

My problem is that I have read data from an input file into an object of one class, but I want to transfer the contents into an object of a different class in an assignment statement. Can this be realized given that the two operands of the assignment operator (=), in this case, would be of two different types?

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C++ :: Class Inside Of Another Class?

Sep 17, 2014

i make a class inside another class, and now i can't create the objects for use the functions of classes.

HEADER:
#ifndef FUNCTIONS_H_INCLUDED
#define FUNCTIONS_H_INCLUDED
class Graphic {
public :
class Draw {

[code].....

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C++ :: Importance Of Static Object In A Class And How They Are Different From General Object

Dec 13, 2012

#include "B.h"
class A {
public :
A()
{
s_b = new B();
b = new B();

[Code] ....

In my project i have seen static object as above . But not able to know what is the exact use of it and how they are different from general object .

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C++ :: Struct At Inside Of Class?

Jun 23, 2013

while writing code i got a question. For example i created a class named as unit.

Think a simple game, and the unit class will belong the units.İf i give the preferences as private one by one, it will be irregular. For a detailed game; height, weight, race, hair preferences, eyes... Strength, dexterity, charisma, intelligence, wisdom, constution... experience, damage, armor...

and should i use struct to group them? And how to can i use struct at the inside of class as private?

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C++ :: Declaring Array Inside A Class

Apr 18, 2013

class Hallway {
private:
//---------------------------------------------------------------
// DO_04: Declare a Light array of size MAX_LIGHTS
// Hint: look through the methods below to find the name to use
// for the array
//---------------------------------------------------------------

int numLights;
int lights[MAX_LIGHTS];

[Code] .....

I keep getting the error " this.lights[i] is not a struct or class and so you cannot use '.' " on line 34.

How am I supposed to define my lights[] array? I can't modify anything except directly after each comment block.

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C/C++ :: Calling Functions Inside A Class?

Nov 4, 2014

Im currently working on a class assignment and the pseudo code containing the instructions that I need to complete list:

//--------------------------------------------------------------------------------------------------------------
// CTOR: Point()
//
// DESCRIPTION
// Default constructor. Initializes the point to be at the origin (0, 0) and the color to black = (0, 0, 0).
//
// PSEUDOCODE
// Call Init() and pass 0, 0, 0, 0, and 0 as the parameters.
//--------------------------------------------------------------------------------------------------------------

My code for this is:

Point::Point(){
void Init(0, 0, 0, 0, 0);
}

The code I wrote for the function Init is here:

Point::Init(int mX, int mY, color mColor){
mX = 0;
mY = 0;
mColor = pInitColor;
}

My problem here is that whenever I try calling this function in the point class, I get an error next to void Init saying incomplete type is not allowed. Also visual studio is telling me that it expects a ')' after my first zero in that line.

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C/C++ :: Offset Function Inside Class?

Jan 1, 2013

i usually use this method for accesing functions in executables, the code is executed from a DLL (always works, except when the function are inside of a class, even tho is public):

.h:

typedef int (*pgObjViewportClose) (OBJECTSTRUCT* gObj);
extern pgObjViewportClose gObjViewportClose;

.cpp

pgObjViewportClose gObjViewportClose = (pgObjViewportClose) 0x04F1940;

That works, but i can't get it to work if the accesing function is inside of a class, i get Unhandled Exception while trying to access a function inside a class, is there a way to do it?.

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C++ :: Accessing Private Members From Inside Class

Jan 10, 2013

Let's say I have the following class:

class MyClass {
private:
int m_myInt;
public:
int myInt() {return this->m_myInt;};
int myFunc();
};

Which of the following is to prefer;

int MyClass::myFunc() {
return 2*this->m_myInt;
}
or
int MyClass::myFunc() {
return 2*this->myInt();
}

The second one seems better? Are both OK? What's the best practice?

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C++ :: Class Definition Inside Function Body

Mar 3, 2013

Is this standard-compliant code?

int f() {
class C {
public:
int mf() const {return 1;}
};
C c;
return c.mf();
}

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C++ :: How To Return Element In Array That Is Inside A Class

Nov 16, 2014

I have a program where I roll a die X number of times and need to print how many times it lands on each side. I tried to create an array in the class aDie that increments each time the corresponding number is rolled but when I go to call and print it in the main my out put is 0. I just picked how many times it landed on the side 4 just to see if it works and it doesn't.

#define ADIE_H
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
using namespace std;
class aDie {

[Code] .....

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