forward declaration of 'const class LHContactInfo' error when try to access it property

I have two c++ class bellow. I want get LHContactInfo property from LHSceneSubclass but I can get nothing.So How can I do with this?

#ifndef __LEVELHELPER_API_CONTACT_INFO_H__
#define __LEVELHELPER_API_CONTACT_INFO_H__

#include "LHConfig.h"
#if LH_USE_BOX2D

#include "cocos2d.h"

class b2Contact;

using namespace cocos2d;

class LHContactInfo
{
public:
    
    LHContactInfo();
    virtual ~LHContactInfo();
    
    Node*       nodeA;
    Node*       nodeB;
    std::string nodeAShapeName;
    std::string nodeBShapeName;
    int         nodeAShapeID;
    int         nodeBShapeID;
    
    Point       contactPoint;
    float       impulse;
    
    b2Contact*  box2dContact;
};

#endif

#endif //__LEVELHELPER_API_CONTACT_INFO_H__


#include "LHContactInfo.h"

#if LH_USE_BOX2D

#include "Box2d/Box2d.h"

LHContactInfo::LHContactInfo(){
    nodeA = NULL;
    nodeB = NULL;
    box2dContact = NULL;
}
LHContactInfo::~LHContactInfo(){
    nodeA = NULL;
    nodeB = NULL;
    box2dContact = NULL;
}

#endif

#ifndef __LH_SCENE_SUBCLASS_H__
#define __LH_SCENE_SUBCLASS_H__

#include "cocos2d.h"
#include "LevelHelper2API.h"

class LHContactInfo;
class LHSceneSubclass : public LHScene
{
public:
    static cocos2d::Scene* createScene();

    LHSceneSubclass();
    virtual ~LHSceneSubclass();
    
    bool initWithContentOfFile(const std::string& plistLevelFile);
    virtual bool shouldDisableContactBetweenNodes(Node* nodeA, Node* nodeB);
    virtual void didBeginContact(const LHContactInfo& contact);
    virtual void didEndContact(const LHContactInfo& contact);
};

#endif // __LH_SCENE_SUBCLASS_H__


//file.cpp

void LHSceneSubclass::didBeginContact(const LHContactInfo& contact){
        if(contact.nodeA->getName() == "box1"){// error invalid use of incomplete type 'const class 
 LHContactInfo'

        }
}
void LHSceneSubclass::didEndContact(const LHContactInfo& contact){
    CCLOG("DIDENDCONTACT...\n");
}

I want to do like contact.nodeA from LHContactInfo in didBeginContact function but compile error ->error invalid use of incomplete type 'const class LHContactInfo'

Note:: - Compile with android NDK 10c

via Chebli Mohamed