/* ::class design guidline::
*
* cohesion -> single entity + immutable
* consistency -> choose informative name, similar operation's name, private in constructor
* encapsulation -> use private modifier to hide info from direct access from clients. getter --> readable, setter --> updateable, if no setter method immutable
* clarity -> you should n't declare a data field that can be derived from other data field
* completeness -> class are designed for use by many different customer
* instance vs static - > it is better use a setter method to change the static data field
* inheritance vs aggregation -> is a(apple is a fruit), has a(person has a name)
* abstrac class vs interface -> what is choose? strong is a relationship(orange is a fruit), weak a relationship(circle, ractangle........ has a area)
*
*/
*
* cohesion -> single entity + immutable
* consistency -> choose informative name, similar operation's name, private in constructor
* encapsulation -> use private modifier to hide info from direct access from clients. getter --> readable, setter --> updateable, if no setter method immutable
* clarity -> you should n't declare a data field that can be derived from other data field
* completeness -> class are designed for use by many different customer
* instance vs static - > it is better use a setter method to change the static data field
* inheritance vs aggregation -> is a(apple is a fruit), has a(person has a name)
* abstrac class vs interface -> what is choose? strong is a relationship(orange is a fruit), weak a relationship(circle, ractangle........ has a area)
*
*/
