advantage:it's more easy to represent the things which are in computer.The symbol bits and other bits can be treated uniformly with complement.The devices that store and manage the data are far less expensive and far reliable if they have to represent only one of two possible values.Also,electronic signals are easier to maintain if they transfer only binary data.

distinguish:A line break is a character coded 10,there is no meaning emerging,only the meaning of control.character has the meaning,and we see the type of the data.