nive. so i added the LiquidCrystal lcd; statement among all the other declarations in the MenuLCD.h, then, i modified my MenuLCD.cpp constructor like this:
MenuLCD::MenuLCD(byte rs, byte enable, byte d4, byte d5, byte d6, byte d7, String intro, MenuItem _menu), lcd(rs, enable, d4, d5, d6, d7)
{
// inizializza le variabili della navigazione
current_menu = 0;
current_sel = 1;
sthToDo = false;
[all the rest]
but the compiler says:
MenuLCD.cpp:8: error: declaration of 'MenuLCD::MenuLCD(byte, byte, byte, byte, byte, byte, String, MenuLCD::MenuItem)' outside of class is not definition
MenuLCD.cpp:8: error: expected constructor, destructor, or type conversion before '(' token