Modify the Tv and Remote classes as follows:
a. Make them mutual friends.
b. Add a state variable member to the Remote class that describes whether the remote control is in normal or interactive mode.
c. Add a Remote method that displays the mode.
d. Provide the Tv class with a method for toggling the new Remote member. 

This method should work only if the TV is in the on state.
Write a short program that tests these new features.