I was confused solving one of my homeworks dealing with even/odd parity. One may recall that:
-In an even parity: the sender make sure that the message send is even, so it just append 0/1 after counting the number of ones.
-In an odd parity it’s the same principle except that the sender make sure it sends an odd number of 1′s
The receiver in counter part will check the parity of the message received depending on the protocol used