{ PA GE }
˜˜˜ 
1: Introduction
to objects
Why has object-oriented programming had such a sweeping impact
on the software development community?
Object-oriented programming appeals at multiple levels. For managers, it promises faster and cheaper
development and maintenance. For analysts and designers, the modeling process becomes simpler and
produces a clear, manageable design. For programmers, the elegance and clarity of the object model and the
power of object-oriented tools and libraries makes programming a much more pleasant task, and
programmers experience an increase in productivity. Everybody wins, it would seem.
If there’s a downside, it is the expense of the learning curve. Thinking in objects is a dramatic departure
from thinking procedurally, and the process of designing objects is much more challenging than procedural
design, especially if you’re trying to create reusable objects. In the past, a novice practitioner of object-oriented
programming was faced with a choice between two daunting tasks:
1. Choose a language such as Smalltalk in which you had to learn a large library before becoming
productive.
2. Choose C++ with virtually no libraries at all,1 and struggle through the depths of the language in order
to write your own libraries of objects.
It is, in fact, difficult to design objects well – for that matter, it’s hard to design anything well. But the intent
is that a relatively few experts design the best objects for others to consume. Successful OOP languages
incorporate not just language syntax and a compiler, but an entire development environment including a
1 Fortunately, this has change significantly with the advent of third-party libraries and the Standard C++ library.