C++ :: Not Declare Object For A Class?
Jul 15, 2013is it possible to don't declare an object for a class and use the function of this class ? i saw a code use this but i cannot find it again .
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C/C++ :: Declare Parent Object Inside Class Constructor
Mar 24, 2014This 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] .....
C++ :: Declare Template Type Object Inside Template Type Class Definition
Oct 12, 2013Let 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.
C++ :: How To Get Object Of Original Class From Function Of Other Class Where Other Class Object Is Member Of Original Class
Jan 21, 2013The 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++
C++ :: How To Forward Declare Inner Class?
Dec 30, 2013How can I forward declare an inner class?
I currently have this:
Code:
class Enigma
{
public:
Enigma()=delete;
Enigma(char r1,char r2,char r3,char r4, char r5, char r6, char r7, char r8, char r9, char r10);
~Enigma(){delete[] R;}
Enigma(const Enigma& rhs)=delete;
Enigma& operator=(const Enigma& rhs)=delete;
[Code]...
I'd like to be able to define Rotor outside of Enigma, but the compiler complains about incomplete types.
C++ :: Declare Class Member Outside Of Constructor?
Jun 27, 2013Basically, I need to set a variable outside of the constructor and make it accessible to the entire class.
It would need to work something like this:
#include <iostream>
#include <string>
template <typename MT> class CallbackFunction
{
[Code].....
C++ :: Forward Declare A Class Template?
Aug 23, 2012i hit the point where i have two class templates that are dependent on each other (in detail, class a stores a pointer of class b), creating a cyclic include issue.
Usually i resolve this with a forward declaration, but i cant seem to figure out how to do it with a template class.In fact, ( i think) i got it to work for this :
Code:
template<typename T>
class a
{
public:
T x;
}
but not for this:
Code:
template<int b>
class b
{
public:
int getb(){return b;}
}
Where the template is not for a specific "type".
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 .
C++ :: How To Declare Array With Constant Size Inside Of Class
Jul 29, 2013I wanted to add that the template argument is needed because its a "special case" but if that doesn't work what would be the next best way to solve this problem. I want to be able to declare the const size of the array outside the class far removed from it actually. I'm actually going off this page
[URL] .....
Heres the code
#include <iostream>
template <int F>
class C
{
[Code]....
C++ :: Declare A Struct / Class In A File For Local Use But With Internal Linkage?
Mar 15, 2013I've been wondering about something for a while:
Is it possible to declare a struct/class, in a cpp file, designed for local use, but with internal linkage?
The usecase is that every once in a while, I want to wrap "startXXX+endXXX" function pairs in a simple RAII struct. I just declare the struct in my cpp and use it once.
However, if I do this, (AFAIK), the compiler will generate an entry in the link table, which means I could potentially have link conflicts if I declare the same struct twice in two different cpp files.
Unless I'm mistaken, since the struct is declared in the same cpp that it is used, I wouldn't need external linkage. Is there a way to avoid it?
C++ :: Transfer Values Set In Privates Of Base Class By Object Of One Derived Class To Another
Apr 26, 2014I 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?
C++ :: Using Member Function Of A Class In Another Class And Relate It To Object In Int Main
Aug 21, 2013I 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] ....
C++ :: Creating One Class Object In Constructor Of Another Class
Sep 20, 2013Suppose I have two classes A and B so how to access object of class A in constructor of B's class as a parameter.
View 6 Replies View RelatedC++ :: How To Create A Class Object Inside Another Class
Feb 20, 2015My 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();
}
C++ :: Initializing Object Of Class Inside Another Class?
Mar 7, 2014I 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
C++ :: How To Declare Class As Forward In Header File - Regular Use In CPP File
Jan 17, 2015lets say we have a valid class with full implementation, X. can this class be declared as forward in Y header file:
Code: class X;
class Y{
X* m_X;
}
but still be used as regular in the cpp file?
Code:
#include "Y.h"
#incldue "X.h"
T Y::function(){
m_X->doSomething();
}
visual studio prevents me from doing it , I wonder if the standard also says so.
C++ :: how To Declare Template Function Inside Template Class
Dec 5, 2013I'm trying to implement a simple template array class, but when i came into the operator< i actually have to use a template :
my code is something like :
template<typename _Type, std::size_t _Size>
class array {
public :
[Code] ......
but i am having an error of shadows template param 'class _Type' is it w/ the name conflict between the array template parameter and the function template parameter ?
C++ :: Declaring Object Of A Class In Another Class
Jul 14, 2014Information:
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.
C++ :: Can Object Of A Class Be Assigned To Another Of Different Class?
Nov 9, 2013I 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?
C++ :: How To Use Object From Another Class
Dec 21, 2013I have two classes one called Date and the other is University , Date class has two overloaded operators , ostream and istream to take in the data and print them out :
ostream & operator<<(ostream & out, Date & x) {
out<< x.month << "/" << x.day << "/" << x.year ;
return out;
[Code] ....
The University class has an object of type Date called establishDate and I must use this to print out the date along with the University name and location, here's University class :
University.h
class University {
public:
University (); // constructor
friend ostream & operator<<(ostream & out, University & x); // print the university data
friend istream & operator>>(istream & in, University & x); // to read university data
[Code] .....
so how do I use the establishDate object ?
C++ :: Converting Object To Different Class
Jun 22, 2014Sandy is of class Person, who converts to Muslim and takes on a new name Fatima, and has all the attributes of Sandy, with new Muslim attributes (e.g. religion == Islam, etc..). At this point, Sandy can be deleted, and Fatima, now of class Muslim will play Sandy's role henceforth. The problem is that due to her new address, all the people who knew Sandy does not know Fatima. Manually changing Sandy's address to Fatima's address for all those people who knew Sandy is clearly not an acceptable method. I looked through all the design patterns and cannot find one to solve this problem. how to improve the design? Here's my simplified code showing the problem:
#include <iostream>
#include <string>
#include <typeinfo>
class Person {
std::string name;
Person* bestFriend;
[Code]...
Output:
sandy = 0x32658, 6Person
Mary's best friend is Sandy.
fatima = 0x23fec0, 6Muslim
Mary's best friend is Sandy.
Of course, we want to have: Mary's best friend is Fatima,. with mary->getBestFriend()->getReligion() == Islam, etc... How to redesign the whole thing so that this is automated (assume there are thousands of people who know her)?
C++ :: Static Object Of Same Class
Jul 27, 2013What is the purpose of having static object of the same class.
E.g.
class someObj{
public:
static someObj obj;
};
how the compiler treats this object
C++ :: Calling Object Within A Class?
May 10, 2014class abc {
public:
int i;
abc * foooo;
};
How do you call * foooo? Say I create:
abc a;
* foooo would have some values for int i.
To get int i of *foooo, I tried a.foooo.i, which doesn't work. How do you call it?
C++ :: Pass Class Object By Reference
Jun 25, 2013I am having trouble working with third party dll's, libs and header files. I am trying to call a function.here is the function that is suppose to be called.
bool COAuthSDK::GetRequestToken(CClientDetails &objClientDetails)
it has this info of what it needs :
Name IN/OUT Description
m_environment IN Optional. Possible values are SANDBOX (default) and LIVE.
m_strConsumerKey IN OAuth consumer key provided by E*TRADE
m_strConsumerSecret IN OAuth consumer secret provided by E*TRADE
m_strToken OUT Returned by the function if successful
m_strTokenSecret OUT Returned by the function if successful
m_strCallback IN Optional; default value is "oob"
here is the COAuthSDK header
#ifndef _OAUTHSDK_H_INCLUDED_
#define _OAUTHSDK_H_INCLUDED_
#include "ETCOMMONCommonDefs.h"
#include "ETCOMMONOAuthHelper.h"
using namespace std;
[code].....
when I try to build the function it says that its in the dll's so I know I have to call it.here is the link to the build site if needed URL....
C++ :: Size Of Object Of Class Child?
Feb 5, 2014hiclass Parent {
};
class Child : virtual public Parent {
};
What is the size of object of Class Child in following case?
C++ :: How To Use A String To Create Class Object
Dec 24, 2014I 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?