关于操作数“=”和“！=”的向量错误的迭代器

using namespace std;
    vector<IDrawable*>::const_iterator itDrawable;
    for(itDrawable= scene.getDrawables().begin(); itDrawable!=scene.getDrawables().end();itDrawable++){
        IDrawable *drawable =(*itDrawable);
        drawable->draw();
    }
using namespace std;
    vector<IDrawable*>::co