qhash with custom class

[dognzhe]

class Tank : public QObject, public QGraphicsItem
{
  Q_OBJECT
 
public:
    Tank(qint16 id,QObject *parent=0,QGraphicsScene *scene=0);
    ~Tank();
     qint16 getTankId(){return tankId;}
private:
      qint16 tankId;
};
 
inline uint qHash(const Tank &key){
 
  return qHash(key.getTankId()); 
}

class Tank : public QObject, public QGraphicsItem
{
  Q_OBJECT

public:
    Tank(qint16 id,QObject *parent=0,QGraphicsScene *scene=0);
    ~Tank();
     qint16 getTankId(){return tankId;}
private:
      qint16 tankId;
};

inline uint qHash(const Tank &key){

  return qHash(key.getTankId()); 
}

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it give me a error:

error C2662: 'Tank::getTankId' : cannot convert 'this' pointer from 'const Tank' to 'Tank &' Conversion loses qualifiers

i have followed the examples in doc. I don't know what the hell going on...

any idea
thanks

[kwisp]

dognzhe,
I think it is no good idea to use qHash name of function in your class, becouse there are many overloaded library`s function named qHash. I think it`s uncomfortably.
May be getHash?

Conversion loses qualifiers

I think, if you use const class reference (const Tank&), you can use const qualifier for it.

qint16& getTankId(){return tankId;}
qint16 getTankId() const {return tankId;}

qint16& getTankId(){return tankId;}
qint16 getTankId() const {return tankId;}

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