PPT Slide

Evolution of an Object (cont’d)

Box_Type definesa record

length isoftype Num

width isoftype Num

height isoftype Num

volume isoftype Num

endrecord

this_box isoftype Box_Type

read(this_box.length, this_box.width,

this_box.height)

this_box.volume <- this_box.length *

this_box.width*this_box.height

Pro:

Grouping of data, better data abstraction: box as data entity, not just a set of variables.

More reusable: can easily get multiple boxes

Con:

Direct manipulation of data

Low procedural abstraction: must think about “how to do it?” instead of “what I want to do?”