Question: What is the widely accepted naming convention for c++ ? (functions, classes, parameters, local variables, namespaces, etc)

Answer: 
I don't think there is a "widely accepted" naming convention in C++. [Stroustrup](http://www2.research.att.com/~bs/)'s books and papers generally has the following coding style:

```
class Shape {
public: // interface to users of Shapes
    virtual void draw() const;
    virtual void rotate(int degrees);
    // ...
protected:  // common data (for implementers of Shapes)
    Point center;
    Color col;
    // ...
};

```

You also may want to look at popular style guides like [The Google C++ Style Guide](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml).
Coding convention is up to you, consistency is what is important. For my own projects, I use [Google's coding style](https://google.github.io/styleguide/cppguide.html).

Stay away from hungarian notation.