C++

Forum

 
 
Circlular Referencing Problem

Sep 20, 2014 at 2:35pm
zxrp (43)
Hey Guys, I am stuck at a part in my program where I can't continue because of an error stating that one of my pointers to a class does not name a type, therefore I am assuming there is a problem with my referencing.

In the bottom code, I think there is a circular referencing problem involving the following classes: PositionMover.h & SwimmingArea.h, I receive an error stating the following:

In file included from PositionMover.h:3:0,
from PositionMover.cpp:1:
SwimmingArea.h:15:8: error: ‘PositionMover’ does not name a type
PositionMover.cpp:3:29: error: expected constructor, destructor, or type conversion before ‘(’ token
make: *** [PositionMover.o] Error 1


Note that this is part of an assignment, so I need the code to work as presented, but how to solve the referencing problem.

My code looks as follows:
(Please note: I am aware that there might be minor errors in the code, however I can't continue to debug because of the current problem.)

Human.h (Just For Reference) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
#ifndef HUMAN_H
#define HUMAN_H

class Human
{
	public:
		Human(char value, int x, int y);
		
		void setValue(char value);
		void setX(int x);
		void setY(int y);
		char getValue();
		int getX();
		int getY();
	private:
		char mValue;
		int mX;
		int mY;
};
#endif


Human.cpp (Just For Reference) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
 
#include "Human.h"

Human::Human(char value, int x, int y)
{
	mValue = value;
	mX = x;
	mY = y;
}

char Human::getValue()
{
	return this->mValue;
}

void Human::setValue(char value)
{
	mValue = value;
}

void Human::setX(int x)
{
	mX = x;
}

void Human::setY(int y)
{
	mY = y;
}

int Human::getX()
{
	return mX;
}

int Human::getY()
{
	return mY;
}


Surfer.h (Just For Reference) 
1
2
3
4
5
6
7
8
9
10
 
#ifndef SURFER_H
#define SURFER_H
#include "Human.h"

class Surfer : public Human
{
	public:
	      Surfer(int x, int y);
};
#endif


Surfer.cpp (Just For Reference) 
1
2
3
4
5
6
 
#include "Surfer.h"

Surfer::Surfer(int x, int y) : Human('X', x, y)
{
    
}


SwimmingArea.h (Problem Here) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
 
#ifndef SWIMMINGAREA_H
#define SWIMMINGAREA_H
#include "Surfer.h"
#include "PositionMover.h"

class SwimmingArea
{
	public:
	      SwimmingArea(int inWidth, int inHeight);
	      ~SwimmingArea();
	      
	      int getWidth() const;
	      int getHeight() const;
	      Surfer* getSurfer() const;
	      PositionMover* createPositionMover(PositionMover* m);
	private:
	      int mWidth;
	      int mHeight;
	      Surfer* mSurfer;
};
#endif


SwimmingArea.cpp 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
#include "SwimmingArea.h"

SwimmingArea::SwimmingArea(int inWidth, int inHeight)
{
    mWidth = inWidth;
    mHeight = inHeight;
    
    mSurfer = new Surfer(mWidth/2, mHeight/2);
}

SwimmingArea::~SwimmingArea()
{
    mWidth = 0;
    mHeight = 0;
    
    delete mSurfer;
}

int SwimmingArea::getWidth() const
{
    return mWidth;
}

int SwimmingArea::getHeight() const
{
    return mHeight;
}

Surfer* SwimmingArea::getSurfer() const
{
    return mSurfer;
}

PositionMover* SwimmingArea::createPositionMover(PositionMover* m)
{
    //Dynamically allocate and return an object of PositionMover
}


PositionMover.h (Problem Here) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
 
#ifndef POSITIONMOVER_H
#define POSITIONMOVER_H
#include "SwimmingArea.h"

class PositionMover
{
	public:
	      PositionMover(){}
	      PositionMover(SwimmingArea* m);
	      
	      void left();
	      void right();
	      void up();
	      void down();
	private:
	      SwimmingArea* mSwimmingArea;
};
#endif


PositionMover.cpp 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
 
#ifndef POSITIONMOVER_H
#define POSITIONMOVER_H
#include "SwimmingArea.h"

class PositionMover
{
	public:
	      PositionMover(){}
	      PositionMover(SwimmingArea* m);
	      
	      //Still have to implement
	      void left();
	      void right();
	      void up();
	      void down();
	private:
	      SwimmingArea* mSwimmingArea;
};
#endif


Any help in order to solve the referencing problem would be greatly appreciated.
Last edited on Sep 20, 2014 at 2:35pm
Sep 20, 2014 at 4:23pm
Disch (13742)
PositionMover.h is including SwimmingArea.h
and SwimmingArea.h is including PositionMover.h

So yeah. Circular reference problem.

I explain the problems/solutions in the below linked thread. If you are interested in a bit of reading, here you go:

http://www.cplusplus.com/forum/articles/10627/#msg49679


If you just want a fix, here is my recommendation:

SwimmingArea.h:
1
2
3
4
5
6
7
8
 
#ifndef SWIMMINGAREA_H
#define SWIMMINGAREA_H
//#include "Surfer.h"    <- get rid of this
//#include "PositionMover.h"  <- get rid of this
class Surfer;  // <- add this
class PositionMover;  // <- add this

// ...


SwimmingArea.cpp
1
2
3
 
#include "Surfer.h"    // <- add this
#include "PositionMover.h"  //  <- add this
#include "SwimmingArea.h"


PositionMover.h
1
2
3
4
5
6
 
#ifndef POSITIONMOVER_H
#define POSITIONMOVER_H
//#include "SwimmingArea.h"  // <- get rid of this
class SwimmingArea;  // <- add this

//...


PositionMover.cpp
1
2
3
4
 
#include "SwimmingArea.h" // <- add this
#include "PositionMover.h"

//...
Sep 21, 2014 at 5:33pm
zxrp (43)
Thank you very much :)
Topic archived. No new replies allowed.