Access violation reading location 0xFFFFFFFFFFFFFFFF

Question

I'm attempting to use OpenGL to demonstrate hierarchical animation. In the early stage I'm trying to give my "bone" object a reference to its parent.

In my bone class, I can add a parent successfully however the issue is when I call hasParent(). It can't read this->parent and crashes with the following exception:

Unhandled exception at 0x00007FF6CB723D43 in myprogram.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF.**

Snippets from my bone class:

void Bone::addParent(Bone *bone)
{
    this->parent = bone;
    assert(this->parent);
}

bool Bone::hasParent()
{
    assert(this->parent); //this line causes the error
    if (this->parent)
        return true;
    else return false;
}

glm::mat4 Bone::getBoneModel()
{
    glm::mat4 parentModel = glm::mat4(1.0);
    if (hasParent())
        parentModel = parent->getBoneModel();
    //boneModel = parentModel * boneModel;
    return boneModel;
}

Stripped down content of my main:

#define NUMBONES 3
Bone bone[NUMBONES];

int main( void )
{
    //------------------ Create Bones --------------------------
    float y = 0.0f;
    for (int i = 0; i < NUMBONES; i++)
    {
        bone[i] = Bone(i, vec3(0, y, -30), vec3(0, 0, 0), vec3(0, 0, 0));
        y += 5.0f;
    }

    //----------------- Make relationships ----------------
    bone[0].isRoot = true;
    bone[0].addChild(&bone[1]);
    bone[0].addChild(&bone[2]);
    bone[1].addParent(&bone[0]);
    bone[1].addChild(&bone[2]);
    bone[2].addParent(&bone[1]);

    do{
        ModelMatrix = bone[1].getBoneModel();
    }
    return 0;
}

I find references and pointers difficult to get my head around so I'm hoping this is obvious to someone else!

EDIT:

My constructors:

Bone::Bone() {
    parent = NULL;
    child = NULL;
    boneID = 0;
    boneModel = glm::mat4(1.0);
}

Bone::Bone(int ID, glm::vec3 T, glm::vec3 R, glm::vec3 S)
{
    boneID = ID;
    isRoot = false;
    pos = T;

    //---------- set boneModel ------------------
    glm::mat4 RotationMatrix = glm::mat4(1.0);
    glm::mat4 TranslationMatrix = translate(glm::mat4(), pos);
    glm::mat4 ScalingMatrix = scale(glm::mat4(), glm::vec3(1.0f, 1.0f, 1.0f));
    boneModel = TranslationMatrix * RotationMatrix * ScalingMatrix;

    std::cout << "bone[" << boneID << "] created.\n";

}

Answer 1

Add

parent = NULL;
child = NULL;

to second constructor Bone(int ID, glm::vec3 T, glm::vec3 R, glm::vec3 S)