2. Assignment 2
P5: Explain where software design and
structures fit into the SDLC
M1: Explain the importance of creating
program code which is of high quality.
Describe how the code quality can be
improved
D1: Discuss ways in which a programmer
can make codes easier to read
2
3. Software Structures
The structure of a program depends on the
type of language used
Procedural languages split the system into
procedures and functions
Object-orientated (OO) languages are based
on objects and classes
Programs are built from combining these
techniques in various patterns and quantities
3
4. Basic Structures
Sequence: Any collection of code statements
that are performed one after the other
Selection: A decision or conditional
statement whose result lets the program
execute one set of code statements or another.
These form the program’s logical pathways.
Iteration (Loops): A block of statements that
are repeated based on some conditional
statement evaluating to true.
4
5. Procedural Structures
Modules: A term used to describe different
parts of a program. These may include
groups of functions and procedures
Procedures: Perform re-usable actions
Functions: Generally used for calculations
as they return value – reusable
Pre-defined code: Built-in functions or a
compiled module which can be inserted into
the solution
5
6. OO Structures
Classes: A program building block which
provides a template for the creation of objects.
A class contains both data and functions that
describe a real-world thing
Objects: A concrete instance of a class,
complete with its own personal data.
Represent either physical or conceptual things
(e.g. customers, books, loans)
Data Abstraction: The object’s users know
nothing about how the data is manipulated
inside the object 6
7. Quality of Code
Reliable and Robust: Thorough testing
ensures programs work properly and can
cope with being used incorrectly
Usability: The best programs are easy to use
and intuitive. Clearly labelled and logically
arranged controls make it easier for the user
Efficiency: The code calculates results and
performs operations as quickly as possible
7
8. Quality of Code
Portability: The ability of a program to run
on different hardware or software platforms
with minimal modification
Maintainability: Every product needs to
be maintained with updates, bug fixes and
new features, to make this easier:
Good detailed technical documentation
describing the design and implementation
Well-written programs inc. Comments,
meaningful variable names and indenting
8
9. Achieving Higher Criteria
M1: Cover all quality issues – explaining
why they may be important in a particular
development project
D1: You need to discuss the readability of
code and the factors that affect it, inc.
Benefits and drawbacks of each technique
used. Give examples of actual code and
explain what problems may arise if the
technique is not used
9
