what is the difference between deriving a class publicly and protectedly ?

Answer 1

public derived class:
private & public base members are private & public
private derived class:
private & public base members are private & private
protected derived class:
private & public base members are protected & protected

Answer 2

http://stackoverflow.com/questions/5447498/what-are-access-specifiers-should-i-inherit-with-private-protected-or-public

Answer 3

but the accessabliry of base members through derived class is same