a. Implement an abstract class Machine with a run method.
b. Then derive two concrete subclasses from Machine: WashingMachine, and Refrigerator.
c. Finally implement a class House that consists of an array of pointers to 2 machines and
astart_running method that starts running all machines of the house.
d. Write a main program that creates a House and runs its both 2 different machines.
Note: run method takes nothing, returns nothing, only prints which machine is running.