Introduction to Programming and Software Development CMPCD1017 Session 1:Introduction to Software...
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Transcript of Introduction to Programming and Software Development CMPCD1017 Session 1:Introduction to Software...
Introduction to Programming and Software Development
CMPCD1017Session 1: Introduction to Software Development
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Content
Software What is Software? Types of Software Why develop new Software?
Introduction to Software Development Process Models The Waterfall Model
Introduction to Computer Programming System Software Languages
Module Overview
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Software
Why is it so important? The economies of ALL developed nations are
dependent on software. 9/11 highlights this with the destruction of the stock
exchange computers More and more of our daily lives are being
supported/monitored by software The engines of our cars Our washing machines Getting on a bus/train
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What is Software?
Software is the part of a computer that makes it useful. In this module we are going to
focus upon application software development.
Software is not tangible. It is ‘conceptual’ so doesn’t wear
out like hardware.
Software is a set of instructions (Programs). These are acted upon (executed)
by the hardware. Software is also the documents
that describe the operation and use of the programs.
Hardware
Operating System
Application{The Computer
Software
• Windows 98/2000/XP• Linux/Unix
• Browser• Email• Word Processor
Sommerville: Chapter 1 & 2
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What does it do?
Generally software takes in data and processes it into information.
The many different types of software basically vary from where/whom data is acquired and where/whom information is sent/given.
Hardware
Operating System
Application
Data In ProcessingInformation
OutFrom the user/device/sub-system
To the user/device/sub-system
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Types of Software
Generic (Off-the-shelf) Applications Well known packages such as word processors,
accounting, image editing, … to name but a few. Anyone is able to buy them.
Bespoke (Customized) Products Systems that are built specifically for individual
people/organisations. They can also be generic software packages that are
customized. The high-cost nature of this type of software
means it is not economically available to all.
Hardware
Operating System
Application
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Types of Software
System Software This type of software exists at the Operating
System layer. It is the operating system itself, compilers, editors….any kind of software that supports the execution and/or development of applications.
Application Software Real-time Software
Programs that monitor/analyse/control real world events. A nuclear power plant cooling system is a good example.
Hardware
Operating System
Application
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Types of Software
Application Software Business Software
Business Information Systems such as payroll, accounts and order management/tracking. There are off-the-shelf packages available for small businesses, however large businesses usually develop their own software.
Engineering and Scientific Software Typically ‘number crunching’ programs for areas such as
astronomy, molecular biology, weather forecasting and Computer Aided Design (CAD) for engineers. Generic programs do exist for some of these areas, however research usually requires new software to be developed.
Hardware
Operating System
Application
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Types of Software
Application Software Embedded Software
Intelligent products such as cookers, washing machines and microwaves use embedded software that typically resides in a Read Only Memory (ROM). Due to the individual nature of such products this software is usually developed/tailored for each.
Personal Computer Software Spreadsheets, word processors, computer graphics,
multimedia and database applications are typical. This type of software is predominantly off the shelf but does go through many versions to remove bugs and increase functionality.
Hardware
Operating System
Application
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Types of Software
Application Software Artificial Intelligence (AI) Software
AI is used to solve complex problems such as scheduling the maintenance of manufacturing equipment to minimise their shutdown. Other uses include pattern recognition (speech/visual). This software is typically newly developed for each application.
The application of computers through software development is only limited by our imaginations……(and its’ cost)
Hardware
Operating System
Application
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Why develop new Software?
As hardware will always eventually wear out, it will need to replaced.
Software on the other hand, doesn’t wear out in this traditional sense, but will become increasingly less useful as users requirements for it changes over time. This means that software needs to be either periodically
updated or replaced.
Understanding the process of software development is therefore paramount in keeping software systems/applications continually useful to its users.
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Introduction to the Software Development Process There are many documented software development
processes; too many to mention here. However, all software development processes can be categorised into: Sequential Process Models
Were software is developed in a sequence of stages, typically: Analyse, Design, Code, Test.
Iterative Process Models Were a sequential process model is repeated until the
software is deemed correct. Typically used when the requirements for a piece of software are not fully known when development starts.
Sommerville: Chapter 3
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The Prototyping Model (Iterative)
This allows the requirements of the system to be explored by the customer.
Once the customer is satisfied with the software system, it can then be taken as the final system or thrown away to allow a fresh system to be developed from the requirements specification.
Listen to customer- Analyse their Requirements
Build/revisemock-up
Customer test-drivesmock-up
Start
FinishSpec
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The Waterfall Model (Sequential) While other process models will be
investigated in this module, we will be focussing upon the central stages of the Waterfall Model of Software Development.
AnalysisDesign
CodeTest
Requirements
Software
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Analysis (Waterfall Model)
The analysis phase of software development aims to develop a requirements specification that can be used to design the new software system.
While there is usually more to a requirements specification, we will be focussing on two of its main parts: Functional Requirements
First, an abstract definition of what the system must do. Then, a detailed set of functional requirements can be
bulleted. Non-functional Requirements
Usually ‘qualitative’ factors such as performance, efficiency and usability are described.
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Design (Waterfall Model)
System design is concerned with how the system functionality is to be provided by the different components of the system. It involves: Requirements Partitioning and Identification of
Sub-systems (if any) Assign requirements to sub-systems and specify
their functionality Define sub-system interfaces
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Design (Waterfall Model)
For each sub-system, a detailed design document is then created. It specifies the structural make-up of the sub-system and
were necessary how data is stored, manipulated and communicated as well as how information is presented.
Design is often an iterative process, especially in a system made up of several sub-systems As problems identified during the design of one sub-system
can cause the re-design of another. Design is typically specified using a mixture of
textual descriptions and structural diagrams.
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Coding (Waterfall Model)
Coding can be seen as simply interpreting the design documents into machine executable instructions. There are many different programming languages
Factors including the application’s domain will help in making a choice of which programming language to use: Platform (Hardware, Operating System, Network), Programming Paradigm (Object-Oriented/ Function-
based/Event-based) Experience of the ‘programmers’ available to do the coding.
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Testing (Waterfall Model)
Testing should start as soon as the requirements specification is available.
A test plan document should be drawn up in parallel with the initial design of the system The plan uses the requirements to provide an
overall testing strategy for the complete system in order to satisfy the following conditions: Verify – Have we built the system right? Validate – Have we built the right system?
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Testing (Waterfall Model)
As a more detailed design for each of the sub-systems is generated, specific testing strategies for each sub-system can be designed
When the code for a sub-system is complete, specific tests for each sub-system can be designed based upon the chosen strategy
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Introduction to Computer Programming(Coding) As mentioned previously, coding is
interpreting a design into a set of instructions for the computer to execute.
There are many languages that can be used to code a program: (Abstractly) High-Level Languages
Java, C, C++, Pascal Low –Level Languages
Assember, Machine Code
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Introduction to Computer Programming In this module we will be using Java, a high-
level language. Although it is an object-oriented language we
will not be teaching or examining on the object-oriented part of the language. Instead we will be using Java as if it were a
functional language, like C or Pascal. The course book supports this approach of using
Java to teach programming in this way.
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Introduction to Computer Programming Throughout the module we will be helping
you understand how programs are built and tested.
Their structural make-up is central to this: Sequence of instructions Iteration of instructions Selection of instructions Grouping of Instructions
In this case Functions
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Module Overview Semester 1
Software Development Process, Project Management, Requirements Analysis and Specification, Testing and Debugging, Problem Solving
Book: ‘Software Engineering’, 7th Edition, Ian Sommerville, Publishers:
Addison Wesley Semester 2
Problem Solving, Design, Coding (Programming) Book:
‘Introduction to Java Programming, Comprehensive’, 5th Edition, Y. Daniel Liang, Publishers: Prentice Hall, ISBN: 0131857215 This book will not be available until December, but will not be
needed until Semester 2
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Module Overview
This module is assessed using 100% coursework Coursework 1 (40% of the module mark)
Given out week starting 1st November 2004 To be handed in 17th January 2005 Several small essay type questions and the production
of a requirements specification and test plan. Coursework 2 (60% of the module mark)
Dates to be confirmed at the beginning of semester 2 Production of a software system, from requirements
specification through design, coding and testing.