Error: Line 12 of Cell.h: 'Actor' undeclared identifier.
If I try to forward declare above it, it says that there's a redefinition. What do I do?
Actor.h:
#ifndef ACTOR_H
#define ACTOR_H
#include <iostream>
#include <vector>
#include <string>
#include "Cell.h"
using namespace std;
class Actor //Simple class as a test dummy.
{
public:
Actor();
~Actor();
};
#endif
Cell.h:
#include <iostream>
#include <string>
#include <vector>
#include "Actor.h"
#ifndef CELL_H
#define CELL_H
using namespace std;
class Cell // Object to hold Actors.
{
private:
vector <Actor*> test;
public:
Cell();
~Cell();
vector <Actor*> getTest();
void setTest(Actor*);
};
#endif
Cell.cpp:
#include "Cell.h"
#include <vector>
vector<Actor*> Cell::getTest() //These functions also at one point stated that
{ // they were incompatible with the prototype, even
} // when they matched perfectly.
void Cell::setTest(Actor*)
{
}
What else can I do?
Remove the #include "Cell.h" from Actor.h and you're set to go.
In general, prefer forward declarations where you can, and includes where you must. I'd also replace the #include "Actor.h" from Cell.h with a forward declaration: class Actor;.
In the cpp files you can include the headers if you need them.
You have recursive #includes via your mutual references between cell.h and actor.h.
In Cell.h, delete #include <Actor.h>.
In Cell.h, add the line class Actor; just above the definition of class Cell.
In Cell.cpp, you might need to add #include "Actor.h".
Related
Can't seem to find where the error is. I do not think there is a circular implementation issue. I am pretty sure all of the .h files are included where they need to be. Array is inheriting from BaseArray:
The error:
In file included from driver.cpp:6:0:
Array.h:10:1: error: expected class-name before ‘{’ token
{
BaseArray.h:
#ifndef _BASEARRAY_H_
#define _BASEARRAY_H_
#include <cstring>
template <typename T>
class BaseArray
{
public...
}
#include "BaseArray.inl"
#include "BaseArray.cpp"
#endif // !defined _BASEARRAY_H_
BaseArray.cpp:
#include "BaseArray.h"
#include <stdexcept>
#include <iostream>
//..Constructors, Destructors, Functions...
Array.h:
#ifndef _ARRAY_H_
#define _ARRAY_H_
#include "BaseArray.h"
#include <cstring>
template <typename T>
class Array: public BaseArray
{
public:
......
};
#include "Array.inl"
#include "Array.cpp"
#endif // !defined _ARRAY_H_
Array.cpp
#include "Array.h"
#include "BaseArray.h"
#include <stdexcept>
#include <iostream>
//
// Array
//
template <typename T>
Array <T>::Array (void): BaseArray<T>()
//...more and more code
Change this:
class Array: public BaseArray
to this:
class Array: public BaseArray<T>
since BaseArray is a template class.
Moreover, in your header file you don't put a semicolon at the end of your class.
I have this code in C++:
#ifndef MYCLASS_H
#define MYCLASS_H
#include "gspace.h"
class myclass {
public:
void update(gspace **);
}
gspace is another class defined in gspace.h. The compiler however is telling me:
include/myclass.h error: ‘gspace’ has not been declared|
Is there anything wrong in what I'm doing?
EDIT:
#ifndef GSPACE_H
#define GSPACE_H
#include <vector>
#include <iostream>
#include <math.h>
using namespace std;
class gspace
{
public:
gspace();
Assuming you have even declared a class named "gspace" in gspace.h I could think of two possible errors.
1) class gspace would not be in global scope i.e could be in some namespace.
2) Please check if header gaurds used in gspace not "MYCLASS_H".
I am trying to compile my code, but I am getting an error with classes. One of the classes compiled fine(Example.h), but the other(Name.h) keeps giving me the class does not name type error. I think it has something to do with circular dependency, but how do I fix that without a forward deceleration?
Name.h
#ifndef _NAME
#define _NAME
#include <iostream>
#include <string>
using namespace std;
#include "Example.h"
class Name{
};
#endif
Example.h
#ifndef _EXAMPLE
#define _EXAMPLE
#include <iostream>
#include <string>
using namespace std;
#include "Name.h"
class Example{
};
#endif
I saw a post about using forward deceleration, but I need to access memebers from the Example class..
You have a circular dependency, where each header tries to include the other, which is impossible. The result is that one definition ends up before the other, and the name of the second is not available within the first.
Where possible, declare each class rather than including the entire header:
class Example; // not #include "Example.h"
You won't be able to do this if one class actually contains (or inherits from) another; but this will allow the name to be used in many declarations. Since it's impossible for both classes to contain the other, you will be able to do this (or maybe just remove the #include altogether) for at least one of them, which should break the circular dependency and fix the problem.
Also, don't use reserved names like _NAME, and don't pollute the global namespace with using namespace std;
see, here you are including #include "Example.h" in Name.h and #include "Name.h" in Example.h. suppose compiler compiles Name.h file first so _NAME is defined now, then it tries to compile Example.h here compiler wants to include Name.h but the content of Name.h will not be included in Example.h since _NAME is already defined, hence class Name is not defined inside Example.h.
you can explicitly do forward declaration of class Name; inside Example.h
Try this:
Name.h
#ifndef NAMEH
#define NAMEH
#include <iostream>
#include <string>
using namespace std;
//#include "Example.h"
class Example;
class Name{
};
#endif
Name.cpp
#include "Name.h"
#include "Example.h"
...
Example.h
#ifndef EXAMPLEH
#define EXAMPLEH
#include <iostream>
#include <string>
using namespace std;
//#include "Name.h"
class Name;
class Example{
};
#endif
Example.cpp
#include "Example.h"
#include "Name.h"
...
Im wanted to create a bidirectional association between 2 classes. For example class A has class B as its private attribute and class B has class A as its private attributes.
Errors which I have gotten is mainly:
Error 323 error C2653: 'Account' : is not a class or namespace name
Error 324 error C2143: syntax error : missing ';' before '{'
(i get loads of such error)
I believe these errors got to do with how i include paymentMode.h in account.h and vice versa. I tried commenting off one inclusion in one of the classes and things work fine. May I ask how to remove such errors while I can still have my bidirectional association between account and paymentMode class?
Thank you!
Attached are the codes that I have written.
//paymentMode.h
#pragma once
#ifndef _PAYMENTMODE_H
#define _PAYMENTMODE_H
#include <string>
#include <iostream>
#include <vector>
#include "item.h"
#include "account.h"
using namespace std;
class PaymentMode
{
private:
string paymentModeName;
double paymentModeThreshold;
double paymentModeBalance; //how much has the user spent using this paymentMode;
vector<Account*> payModeAcctList;
public:
PaymentMode(string);
void pushItem(Item*);
void addAcct(Account*);
string getPaymentModeName();
void setPaymentModeName(string);
void setPaymentModeThreshold(double);
double getPaymentModeThreshold();
void setPaymentModeBal(double);
double getPaymentModeBal();
void updatePayModeBal(double);
int findAccount(string);
void deleteAccount(string);
};
#endif
//account.h
#pragma once
#ifndef _ACCOUNT_H
#define _ACCOUNT_H
#include <string>
#include <iostream>
#include <vector>
#include "paymentMode.h"
using namespace std;
class Account
{
private:
string accountName;
//vector<PaymentMode*> acctPayModeList;
double accountThreshold;
double accountBalance; //how much has the user spent using this account.
public:
Account(string);
//void addPayMode(PaymentMode*);
//int findPayMode(PaymentMode*);
string getAccountName();
void setAccountName(string);
void setAccountThreshold(double);
double getAccountThreshold();
void setAccountBal(double);
double getAccountBal();
void updateAcctBal(double);
};
#endif
You have a circular include dependency, but in this case, since class A only holds a container of pointers of class B, and vice versa, you can use forward declarations, and put the includes in the implementation files.
So, instead of
#include "account.h"
use
class Account;
Unrelated: do not put using namespace std in header files, and if possible, nowhere. See here for more on that issue.
What is going on?
#include "MyClass.h"
class MyOtherClass {
public:
MyOtherClass();
~MyOtherClass();
MyClass myVar; //Unknown type Error
};
Suddenly when I include the .h and write that var Xcode gives me tons of errors... and also the unknown type error.
How can it be unknown when the .h is included right there?
Here is the NodeButton.h file which would correspond to the MyClass.h in the example
#pragma once
#include "cinder/Vector.h"
#include "cinder/gl/gl.h"
#include "cinder/gl/Texture.h"
#include "cinder/Color.h"
#include "cinder/ImageIo.h"
#include "cinder/Timeline.h"
#include "cinder/app/AppBasic.h"
#include "cinder/App/App.h"
#include "Node.h"
#include "CursorMano.h"
using namespace ci;
using namespace ci::app;
using namespace std;
using namespace is;
typedef boost::shared_ptr<class NodeButton> NodeButtonRef;
class NodeButton : public Node2D
{
public:
NodeButton (CursorMano *cursor, string imageUrl, bool fadeIn = false, float delay = 0.0f);
virtual ~NodeButton ();
//methods
void update( double elapsed );
void draw();
void setup();
//events
bool mouseMove( ci::app::MouseEvent event );
//vars
CursorMano *mCursor;
gl::Texture mImageTexture;
Anim<float> mAlpha = 1.0f;
bool mSelected = false;
private:
};
And here are the contents of CursorMano.h which would correspond to MyOtherClass.h in the example.
#pragma once
#include <list>
#include <vector>
#include "cinder/app/AppBasic.h"
#include "cinder/qtime/QuickTime.h"
#include "cinder/gl/Texture.h"
#include "cinder/Vector.h"
#include "NodeButton.h"
using namespace ci;
using namespace ci::app;
using namespace std;
class CursorMano {
public:
CursorMano (AppBasic *app);
~CursorMano ();
void mueveMano(Vec2i);
void update();
void draw();
void play(int button);
void reset(int button);
Vec2i mMousePos;
NodeButton mButtonCaller; //this gives the unknow type error
private:
AppBasic *mApp;
gl::Texture mFrameTexture;
qtime::MovieGl mMovie;
int mIdButton;
};
You have a circular dependency of your header files.
NodeButton.h defines NodeButton class which CursorMano.h needs to include so that compiler can see definition for NodeButton but NodeButton.h itself includes CursorMano.h.
You will need to use forward declarations to break this circular dependency.
In NodeButton.h you just use an pointer to CursorMano so You do not need to include the CursorMano.h just forward declare the class after the using namespace declarations.
using namespace std;
using namespace is;
class CursorMano;
It's probably a result of the circular dependency between you two header files (NodeButton includes CursorMano and CursorMano includes NodeButton). Try removing the #include "CursorMano.h" in NodeButton.h and add class CursorMano; before your NodeButton declaration.