To promote the development of robust and reusable software take a consistent object-oriented viewpoint data should be presented as being encapsulated with the methods that access and modify them think of data objects as instances of an abstract data type (ADT), which includes a repertoire of methods for performing operations on data objects of this type there may be several different implementation strategies for a particular ADt, and explore the relative pros and cons of these choicesTo promote the development of robust and reusable software • take a consistent object-oriented viewpoint • data should be presented as being encapsulated with the methods that access and modify them. • think of data objects as instances of an abstract data type (ADT), which includes a repertoire of methods for performing operations on data objects of this type. • there may be several different implementation strategies for a particular ADT, and explore the relative pros and cons of these choices