does not have field named [duplicate]

Question

I have a mistake I cannot understand when initializing member data in an inherited class with two different methods I thought they should be theoretically identical.

class gSolObject
    {
    public:
        gSolObject();
        virtual ~gSolObject(){}
        bool   isCollisionObject;
    };

class gPlanetObject : public gSolObject
    {
    public:
        gPlanetObject();
       ~gPlanetObject(){};
    };

gSolObject::gSolObject():isCollisionObject(1)
            {
            }

gPlanetObject::gPlanetObject():gSolObject(),isCollisionObject(0)
            {
            }

I get an error class 'gPlanetObject' does not have any field named 'isCollisionObject'.

However when I put the initialization right into the constructor's brackts {..} instead:

gPlanetObject::gPlanetObject():gSolObject()
            {
            isCollisionObject=0;
            }

It compiles fine. Why would that be?

EDIT: This also does not work

gPlanetObject::gPlanetObject():gSolObject(),gSolObject::isCollisionObject(0)

It writes 'expected class-name before '(' token'

Answer 1

You can't initialize member variables declared in base classes, because the base class constructor has already initialized them. All base constructors execute before member constructors.

You can reassign it. Or you can call a base class constructor that takes an argument and initializes its members with that value.

Answer 2

Edited : You can't call a method of a uninitialized object (here gSolObject) and that's why it works when you execute isCollisionObject(0) in the constructor. Furthermore, if you always set it to 0, then you should use default value in the gSolObject constructor.