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PROGRAM
DEVELOPMENT LIFE
CYCLE

Programming
RISHI RANA
115358
D1 CSE N2

PROGRAMMING

Creating algorithms is the
precursor to creating programs;

An algorithm is the blueprint, so
to speak, of a computer program.

Recall that the general problem-solving
process has 5 phases

1.Defining the problem
2.Analysing the problem
3.Identifying and Evaluating
Possible Solutions
4.Selection and Justification of
the Optimal Solution
5.Implementation and Review

In phase 5 the organisation gets a
new system

This system is made up of
hardware, software, people and
procedures

The process of creating this new
system is called the SDLC

SDLC means the ...

Systems
Development
Life
Cycle

The
Systems Development
Life Cycle
is therefore something of
a sub-process inside a
larger overall process

The
Systems Development
Life Cycle
is a model used to guide
Information Technology
professionals through the
management of Information
Technology projects to create
a new computer system

The Phases in the
Systems Development Life Cycle
are :

1.Feasibility Study
2.Analysis
3.Design
4.Implementation
5.Testing
6.Maintenance

"Implementation and Review" therefore, is
also done in stages.

Note carefully that the SDLC may mean :

- implementing a system which uses a
general purpose computer program
or
- implementing a system that uses another
type of off-the-shelf or pre-existing package

or it may mean

- implementing a system that
requires the organisation to
employ/use a programmer or a
team of programmers or a
software house to create a
custom-written software
package

If the organisation chooses to buy a
pre-existing computer software
package, it simply has to be purchased
and installed, and the staff trained to
use it.

They may also have to carry out
conversion activites i.e. somehow
copying the data they presently have
into the new program

However, if the software to
meet the organisation's needs
does not presently exist, then
in the "implemtation and
review" stage of problem
solving, a new software
package has to be created.

In such cases the SDLC is
more than just putting a
system in place but would
also have to involve
creating a new software
package.

Creating a new software
package means that the
project involves more than
just systems analysts, it
also needs programmers

Systems analysts evaluate
the information technology
needs of an organisation
and prescribe and design
new systems for them.

Computer programmers,
on the other hand, develop
and maintain the
instructions to a computer
(software) which are
written in a computer
language

Computer programmers
take instructions from
systems analysts as to what
the computer program is to
look like and what it is to
do

Working together
they carry out a
particular variant of
the SDLC called the
PDLC

The process of
creating new software
is called the
Program
Development Life
Cycle

Program Development
Life Cycle
The progam development life
cycle is the process of developing
a software according to the
desired needs of a user by
following a basic set of
procedures

While the SDLC is about the
entire system, the
Program Development
Life Cycle
is concerned principally with how
a new software program comes
into being and is continually
maintained over its lifetime

Program Development
Life Cycle
The progam development life
cycle involves
•users
•systems analysts
•programmers and
•testers

Program Development
Life Cycle
The steps in program development
are :
1.Requirements Definition
2.Design
3.Implementation / Coding
4.Testing
5.Maintenance

Program Development
Life Cycle

Program Development
Life Cycle
Step 1

A requirement is a document which
details the needs of a customer in a
service or a product

Program Development
Life Cycle
Step 1
1.Requirements
Definition
This is a critical component in the process.
Users often have a vague idea of what they
want in a program. It is the analyst's job to
help them to flesh out these ideas

Program Development
Life Cycle
Step 1

Requirements definition is the process
of eliciting and documenting what the
users need in a computer program

Program Development
Life Cycle
Step 1

Incomplete or inaccurate requirements
result in schedule delays, wasted
resources and customer dissatisfaction

Program Development
Life Cycle
Step 1
At the end of the requirements
definition phase the systems analyst
produces a document called the
system specifications

Program Development
Life Cycle
Step 2
2. Design
In the design phase of the Program
Development Life Cycle the systems
developer/software engineer creates the
algorithm.
The algorithm may be expressed as
pseudocode and/or flowcharts

Program Development
Life Cycle
Step 2
2. Design
They may use techniquse such as
•modular programming
•top down design
•bottom up design
•structured programming

Program Development
Life Cycle
Step 3
3. Implementation/Coding
Coding means translating the algorithm into
computer language format. The programmers
who do this are also responsible for testing
their results to ensure, in particular, that it
contains no syntax errors

Program Development
Life Cycle
Step 4
4. Testing
The program is given to a group of
specialist testers and/or a group of user
representatives who run it and verify
that it performs according to the
specifications developed in step 1

Program Development
Life Cycle
Step 5
5. Maintenance
Over the life of a program, user needs
or statutory requirements will mean
that the program needs to be amended
sometimes. This is what maintenance is
about.

Program Development
Life Cycle
Documentation
Some books list documentation as a separate
step in the process and some do not.
This is because documentation takes place
over the life of the project. As one works every
step of the way everything should be
documented.

The PDLC is a cyclical
process

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