-> unsigned char _alpha as date member. The constructor define _alpha=120 by def
ault. Acces function for alpha and set function for alpha
##Constructor : (modified)
Color(unsigned char red, unsigned char green, unsigned char blue, unsigned char
alpha = 120)
: _red(red), _green(green), _blue(blue), _alpha(alpha)
{}
## access to alpha :
unsigned char alpha() const {return _alpha;} (added)
## set alpha
void set_alpha(unsigned char a) {_alpha=a;} (added)
## modified to match alpha new data member :
operator=
## adding new colors : defined in Color.C
extern const Color ORANGE ;
extern const Color GRAY ;
extern const Color DEEPBLUE ;
extern const Color PURPLE ;
That's all.