Software Engineering DKT311 ROHANI BINTI S MOHAMED FAROOK MOHAMED ELSHAIKH KKF 8A – room 4

Course overview  Lectures 60% Wednesday 1 – 3 pm at BKQ 6  Lab 40% Thursday 9 – 11 am at MKQ1 As follow: Final exam 50% Practical 50%  lab assignment 30%  test 10%  Lab test 10%

Guide lines  Early study Object-Oriented Software Engineering Practical software development using UML and JAVA, 2 nd edition, (Timothy C. Lethbridge and Robert Laganiere) Lecture notes provided materials Take notes during the lecture  Assignments For self development Counted lab assignment

Course outcomes  to describe software engineering concepts and terms used in its discipline  to analyze a problem based on different software development models, to write specification document based on the standard documentation  to design and develop software prototype based on the specification and verification and validation  to apply software engineering skills to project management

Lecture 1.  Software and software engineering  Software Engineering definition  Difference between computer science and  software engineering  Review to Object Orientation  Class and objects  Instances variables  Methods, operations and polymorphism  Inheritance

Questions you need to answer  What is software?  What is software engineering?  What is the difference between software engineering and computer science?  What are the costs of software engineering?  What are software engineering methods?  What are the attributes of good software?  What are the key challenges facing software engineering?

What is software  Computer programs and associated documentation such as requirements, design models and user manuals.  Software products may be developed for a particular customer or may be developed for a general market.  Software products may be Generic - developed to be sold to a range of different customers e.g. PC software such as Excel or Word. Bespoke (custom) - developed for a single customer according to their specification. Embedded software – to adopt hardware functionality.  New software can be created by developing new programs, configuring generic software systems or reusing existing software.

Software problems  Software crisis Poor software design. Doesn't meet their expectations. Never delivered or late delivered. Over budget. Software bugs.  Software engineering methods To meet expectations. Avoid crisis.

Software designing artifacts  Software unlike other engineering products are: Illusive. Low mass production. Un-engineered designs are easy to collapse. no expiry date.

Software engineering  Solve problems Economically systematic High quality Satisfactory Reliable Maintainable Flexible

Other definitions  IEEE: (1) the application of systematic, disciplined, quantifiable approach to the development, operation, maintenance of software ;that is, the application of engineering to software. (2) the study of approaches as in (1).  The Canadian Standards Association: the systematic activities involved in the design, implementation and testing of software to optimized its production and support.

Software engineering vs. computer science  Computer science is concerned with theory and fundamentals; software engineering is concerned with the practicalities of developing and delivering useful software.  Computer science theories are still insufficient to act as a complete underpinning for software engineering (unlike e.g. physics and electrical engineering).

Stakeholders software USER CUSTOMERS DEVELPER MANAGMENT SOFTWARE DEVELOPER

Stakeholders  Users Those whom use the software  Customers Start design (decision)  Software developers Develop. Maintenance. Software engineers Recognized by their high quality work. Work in teams.  Development manager Companies managers. Always looking for profit ( low design cost & pleasing customers. quality developercustomermanageruser

Software quality  Is this a high quality software? Customer:  Solves my problem.  Low cost (money and resources). User:  Easy.  Efficient.  Get job done. quality developercustomermanageruser

Cont.  Developer: Easy to design Maintainable Reusable  Development manager: More selling Satisfactory Low design & maintaining cost Developer Easy to design Maintainable Reusable

Quality software Customer Solve my problems Not costed User EasyEfficientGet job done Developer EasyMaintainableReusable Manager Low design cost More sell Satisfactory

Cont.  It is very hard to say this is a high quality software, but we may consider the most important five quality attributes:  Usability  Efficiency  Reliability  Maintainability  Reusability

Cont.  Make your objectives  Internal quality Comments Complexity  Short term Does it meets the immediate needs? Sufficient, efficient for today data?  Long term quality What about maintainability? What about future needs?

Software engineering project  Team work Few people for small projects What about big projects  Three categories: Evolutionary project  Modifying Greenfield project  Developing from scratch Build from existing components  Uses frameworks  New for missed details

Common project activity  Project life cycle:  Requirement and specification Understanding the problem  Design How to implement the requirements  Modeling Software representation

Cont.  Programming Translate what you did to high level programming language (coding)  Quality assurance Meet the quality objectives  Reviews and inspections  Testing  Deployment Distributing and installing the system

Cont.  Managing the software configuration Identifying the components All software engenderers must participate for their components.  Managing the process Estimate the cost of the system Planning

Object Orientation (OO)  In it is very common name OOP Object oriented programming  Abstraction “software less complex”  Combines procedural abstraction with data abstraction?  Class and objects  Instances variables  Methods, operations and polymorphism  Inheritance

Abstraction  Data abstraction Records and structures Entity description  Procedural abstraction Function and procedure Action description OOP is: The object oriented paradigm is approach to the solution of problems in which all computations are performed in the context of object. The objects are instances of programming constructs, normally called class, which are data abstractions and which contain procedural abstractions that operate on the object.

Class & Object  Represents the abstracted entity into: Properties  To describe the current state.  (what is your car color?) Behavior  The acts and reacts of the object.  (I may change my car color..)  Class is a software module that represents and defines a set of similar objects.  Object is a chunk of structure data in a running software. Lets look at some examples…

Human as a class

Accounting system

Instances variables  Objects are class’s instance  Example: Student Name: Id: School: Grade: Change school. Change course. Withdraw. Mohamed Computer B Name Attributes methods

Ex.  General motors  Boeing 777  Mary smith  Board game  University course SEG 2100  The game of chess between tom and jane  Automobile company  Chess  Airplane  The car with serial number WQH 8062

Methods, operations and polymorphism  Method = function, procedure It used to implement the behavior of class  Operation High level procedural abstraction To specify type of behavior  Polymorphism Is a property of object oriented software by which an abstract operation may be performed in different ways, typically in different classes.

Polymorphism  Example: Bank interest  Average daily balance  Minimum daily balance  Can you give another example…. Car Student

Inheritance  Classes with common attributes To avoid duplication Super class contains the common attributes Account Saving account Checking account Current account Inheritance is the implicit possession by a subclass of features defined in the super class. Feature include variables and methods.

AAny question. TThank you…..

Questions for this lectures  Define the following terms: Software engineering(IEEE, Canadian Standards Association) Software The differences between software and software engineering? Object, Class, polymorphism, inheritance. Stockholders Software engineering quality

 Describe the role of each stockholder in a software engineering project?  Draw a class box for each of the following stating the class name, attributes, and methods: Cars Students Server Human Home

 In example project there are two classes namely (Human, student, lecturer, child), draw a diagram showing the inheritance relationship between these classes.