Iterator on vector error for operands "=" and "!=" - c++

Question

using namespace std;
vector<IDrawable*>::const_iterator itDrawable;
for(itDrawable= scene.getDrawables().begin(); itDrawable!=scene.getDrawables().end();itDrawable++){
IDrawable *drawable =(*itDrawable);
drawable->draw();
}
This code is passing me the error:
Description Resource Path Location Type no match for 'operator!='
(operand types are 'std::vector<IDrawable*>::const_iterator {aka
__gnu_cxx::__normal_iterator<IDrawable* const*, std::vector<IDrawable*> >}' and 'std::vector<const
IDrawable*>::const_iterator {aka __gnu_cxx::__normal_iterator<const
IDrawable* const*, std::vector<const IDrawable*> >}')
And
Description Resource Path Location Type no match for 'operator='
(operand types are 'std::vector<IDrawable*>::const_iterator {aka
__gnu_cxx::__normal_iterator<IDrawable* const*, std::vector<IDrawable*> >}' and 'std::vector<const
IDrawable*>::const_iterator {aka __gnu_cxx::__normal_iterator<const
IDrawable* const*, std::vector<const IDrawable*> >}')
I have looked these up and i should have something to do with the const_iterator ?
yet my scene.getDrawables() looks like:
const std::vector<const IDrawable*>& getDrawables() const {
return drawables;
}
So the iterator should be a const_iterator right ?
I have no clue what has to change...

Answer 1

Your
const std::vector<const IDrawable*>& getDrawables() const
returns a const reference to a vector of const IDrawable* pointers. However your
vector<IDrawable*>::const_iterator itDrawable;
declares a const_iterator to a vector of different type (IDrawable*, not const IDrawable*). Either change the definition to vector<const IDrawable*>::const_iterator itDrawable; or simply use auto to declare the iterator in your for loop,
for(auto itDrawable= scene.getDrawables().cbegin(); ...)

Answer 2

The formatting of your question hides the real problem, but you used:
vector<IDrawable*>::const_iterator itDrawable;
where you should have used
vector<const IDrawable*>::const_iterator iDrawable;
Likewise, you then need
const IDrawable *drawable =...
instead of
IDrawable *drawable =...
All this due to the fact that you have a std::vector<const IDrawable*>.