Page 111 - DCAP405_SOFTWARE_ENGINEERING

Software Engineering

Notes the added portion. If there are any errors detected then they are already partly isolated so they
are much easier to correct.
A carefully planned incremental development process can also ease the handling of changes in
requirements. To do this, the planning must identify use cases that are most likely to be changed
and put them towards the end of the development process.

Consistency

The principle of consistency is recognition of the fact that it is easier to do things in a familiar
context. For example, coding style is a consistent manner of laying out code text. This serves two
purposes. First, it makes reading the code easier. Second, it allows programmers to automate
part of the skills required in code entry, freeing the programmer’s mind to deal with more
important issues.

At a higher level, consistency involves the development of idioms for dealing with common
programming problems.
Consistency serves two purposes in designing graphical user interfaces. First, a consistent look
and feel makes it easier for users to learn to use software. Once the basic elements of dealing
with an interface are learned, they do not have to be relearned for a different software application.
Second, a consistent user interface promotes reuse of the interface components. Graphical user
interface systems have a collection of frames, panes, and other view components that support
the common look. They also have a collection of controllers for responding to user input,
supporting the common feel. Often, both look and feel are combined, as in pop-up menus and
buttons. These components can be used by any program.
Meyer applies the principle of consistency to object-oriented class libraries. As the available
libraries grow more and more complex it is essential that they be designed to present a consistent
interface to the client.

Example: Most data collection structures support adding new data items. It is much
easier to learn to use the collections if the name add is always used for this kind of operation.
Self Assessment

Fill in the blanks:

1. A data structure component is often easier to use if these two concerns are divided as much
as possible into separate sets of………………………….
2. After the software is design to meet other criteria, it’s …………………….. can be checked
and analysed to see where the time is being spent.

3. A software developer can think in terms of graphs and graph algorithms without attaching
concrete meaning to ………………………. and edges.
4. It is important in …………………….. software that is free from unnatural restrictions and
limitations.
5. The principle of ………………….. is recognition of the fact that it is easier to do things in
a familiar context.
6. Graphical user interface systems have a collection of frames, …………………….. , and
other view components that support the common look.
7. A carefully planned incremental development process can also ease the handling of changes
in………………………………...

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