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,
how can I make the queue of type pcb
and how to access pid in other clases?
How can I add the variable adress to a void pointer inside of a class?
class variant2 {
private:
void *Vvariant=NULL;
public:
template<typename b>
variant & operator = (b *adress)
[Code] ....
if possible i want avoid the '&' when i assign the variable address.(variant2 f=varname;//like you see i don't use the '&')
for the moment i just need put the address to Variant pointer. but i receive several errors .
recently I developed a class header only in C++ to deal with byte arrays. Since I developed programs in other languages that had some libraries to dial with byte arrays, I developed one that the syntax is very similar to other languages.
Since I'm not very familiar with memory management, I was concerned about somethings I've read about (ex: memory fragmentation).
Here is a very simple example of my practice:
class ByteArray {
public:
ByteArray(size_t size) {
buffer = (int8_t*)malloc(size);
}
[Code].....
The class is intended to be used as part of comunication protocol in a webserver, byte arrays are created and destroyed a lot. Should I use pools? Is there a better practice? Am I doing everything wrong (laugh)?
For those who wants to see the entire class: [URL]
In VC++ is there any inbuilt class for storying values inside an XML File, without using CLI?
View 14 Replies View Relatedit 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.
I have written a class "FileSet " in program's Document class.
This class contains other Four classes as
"Machine1" , "Machine2", "Machine 3" and "Machine 4".
Now my problem is Machine 1 can not access variables from Document class or other variables from FileSet.
How to access them ?
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] .....
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();
}
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
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 RelatedI cannot wrap my head as to how to access my enum class Azimuth.
Code: #ifndef BOUSOLE_H
#define BOUSOLE_H
#include <iostream>
#include <string>
#include "StringHandler.h"
class Bousole{
[code]...
And here is where I am trying to access my enum for testing/understanding purposes
Code: #include "Bousole.h"
using namespace std;
int main (int argc, char *argv[]){
cout <<"Start bousole" << endl;
Bousole b;
[Code] ....
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] .....
if we don't provide the acces modifiers for base class and we need to manipulate the private data of base class in derived class. Is there anyway to acces the private data members? Here's a coding example
class A {
private :
int a;
};
class B : public class A {
public :
void displayA() { cout<<a<<endl; }
};
how i can acces the a of base class A in derived class B without acces modifiers.
Why the void pointer passed to testb doesn't continue pointing to the allocated integer after the function call returns.
Code:
#include <stdio.h>
#include <iostream>
void* testa() {
return new int(1);
[Code] ....
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].....
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.
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?
#include "IMyIntData.h"
class MyIntData : public CPMUnknown<IMyIntData>
{
I need to know what this syntax means (including MyIntData in angular brackets after parent class name) where IMyIntData is the Interface from where MyIntData is derived.
My program is a basic MFC AppWizard (exe) created project in VC++ 6. In MainFrm.cpp, I am trying to access some user defined CMyView member functions. However when I try to do the standard procedure to get the CMyView pointer in MainFrm.cpp, I get the " ... 'CMyView' : undeclared identifier" error. To resolve this, I add " #include myView.h " at the top of MainFrm.h which then produces the following errors:
Code:
myview.h(21) : error C2143: syntax error : missing ';' before '*'
myview.h(21) : error C2501: 'CMyDoc' : missing storage-class or type specifiers
myview.h(21) : error C2501: 'GetDocument' : missing storage-class or type specifiers
What do these errors mean? Is there a simple way to access CMyView member functions from CMainFrame?
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.
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.
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.
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?.
I have encountered a problem I can't see to solve. I want to access a function and can't seem to find the right combination to get me there. Here is what I am looking at:
CFoo1::CFoo2::GetStrDataC(int nRow) const
How do I call the GetStrDataC function from another class?
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?
