Two C++ questions.

[Angus Leeming]

QUESTION 1
==========
If I have a struct NamedColor
        struct RGBColor {
                int r, g, b;
        };
        struct NamedColor : public RGBColor {
                string name;
        };

and then I create a database of colors, so:
        vector<NamedColor> colorDB;

then why can't I do:
        colorDB.erase();
?

cxx bombs out with
cxx: Error: FormPreferences.C, line 828: #304 no instance of overloaded
          function "std::vector<T, Allocator>::erase [with T=NamedColor,
          Allocator=std::allocator<NamedColor>]" matches the argument list    

what do I need here?

QUESTION 2
==========
Can I "merge" two vectors of the same kind to create a new, larger vector. 
Something like:

        vector<NamedColor> redDB = ...'
        vector <NamedColor> orangeDB = ...;
        vector <NamedColor> colorDB = redDB + orangeDB;

Many thanks,
Angus