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Phases in Software Development Cycle: Program Specifications, Design, Coding, Testing, Installation, Documentation, and

This lecture covers the different phases in the software development cycle, including program specifications, design techniques, coding, testing, installation, documentation, and maintenance. It also introduces object-oriented programming and its benefits.

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Phases in Software Development Cycle: Program Specifications, Design, Coding, Testing, Installation, Documentation, and

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  1. 14 CHAPTER Programming MIS105 Week-15/ Lec02 Irfan Ahmed Ilyas

  2. Lecture Objectives • Phases in Software Development Cycle • Phase1: Program Specifications • Phase2: Program Design (Documentation Techniques) • Psuedo code • Flow charting • Phase 3: Program Coding • Phase 4: Program Testing • Phase 5: Installing the Program • Phase 6: Program Documentation • Phase 7: Program Maintenance Prepared By: Irfan Ilyas

  3. 21 4A5E 4096 A Machine Language Instruction 3. Program Code • Program design/ flow chart logics are transferred to Computer Language Code • Two main types of ComputerLanguages • Low Level (Machine Languages) • A computer’s own internal language • Different for every computer • Very complex to write programs • Memory addresses need to be used literally • Example: machine code of Intel x86 processors or Prepared By: Irfan Ilyas

  4. LET TOTAL = AMT1 + AMT2 A program instruction in Quick Basic … 3. Program Code • ….Main types of Computer Languages • High Level (Symbolic Languages) • Uses English like syntax • Commonly used on different hardware platforms • Much easier to use than machine languages • Simple symbolic names can be used for Memory addresses • Needs a translator program (compiler) to generate the equivalent machine code • Examples: Quick BASIC, C++, Java Prepared By: Irfan Ilyas

  5. ….2- Example ( Advantage Advertising)C++ Code for“Compute time for Client A” Prepared By: Irfan Ilyas

  6. …3. Program Code (Issues) • A variety of High Level Languages are available, including • Visual Basic, • Visual C • Java • Small Talk • Fortran • Selecting a particular language depends upon • The expertise of the programmer • Resources available for the program (hard-disk space, monitor type etc.) • The application area of the program Prepared By: Irfan Ilyas

  7. 4. Program Test (Debugging) • Process of removing bugs (errors) from a program • Possible error types • Syntax Errors (Coding Errors) • Coding incorrectly • Causes: Typing mistakes/ violating language rules • Example: • PRNT “Hello” ‘A syntax error in PRINT statement of Quick Basic • printf(“%s: %d”,”Result”,x) ‘In C++, statement does not end with a semicolon (;) Prepared By: Irfan Ilyas

  8. …4. Program Test (Debugging) • ….Possible error types • Logic Errors (Algorithm Errors) • Mistakes in algorithm steps • Results in • incorrect outputs • Run-time crashes • Causes: • Mistakes in the instruction sequence • Using inappropriate instructions • Not very obvious when happening with some particular values of data inputs Prepared By: Irfan Ilyas

  9. …4. Program Test (Debugging) • How to debug? • Syntax Errors • Carefully comparing the program with the language valid codes • Captured automatically by the translator programs (compilers) • Logic Errors • Running the program with test data (input values for which correct results are known) • Logic errors are pinpointed when • a known input-output pair doesn’t match • Program crashes for some input values. • Debugger Programs are available (with almost all language compilers) to pinpoint logic errors Prepared By: Irfan Ilyas

  10. …4. Program Test (Debugging) • Standard program testing procedure • Desk checking • Manual testing with sample (test) data • Attempt at translation • Testing sample data on computer • Testing by a selected group of potential users (beta users) Prepared By: Irfan Ilyas

  11. 5. Installing the Program • A program is usually implemented as part of an overall, integrated information system • Example: • An Accounting Information System • Composed of many different programs (built independently) • Each program works for a different accounting area like general ledger, payroll etc. • The programs are then implemented in an integrated manner to bring up the overall information system Prepared By: Irfan Ilyas

  12. 6.Program Documentation • Documentation explains every facet of a program (usage, development, error-handling) • Should be on-going throughout program development • Should be compiled and organized at the final stages • Addresses three possible communities • Program Users • Program Operators • Program Developers Prepared By: Irfan Ilyas

  13. 7. Program Maintenance • Two broad Maintenance categories • Correction of emerging errors • Modification for changing user needs • Significantly consumes the share of total development time (>75%) • Mostly done by specially hired programmers (Maintenance Programmers) Prepared By: Irfan Ilyas

  14. Introducing Object Oriented Programming Prepared By: Irfan Ilyas

  15. Lecture Objectives • Introducing Object Oriented Programming (OOP) • Classes & Objects • Attributes & methods • Benefits of OOP • Reusability (inheritance) • Hiding complexity (encapsulation) • Context driven functionality (polymorphism) Prepared By: Irfan Ilyas

  16. … Lecture Objectives • Introducing Microsoft Access VBA Programming • Concept of Microsoft Access application • VBA- Object based Programming • Microsoft Access Objects • Event driven programs • Event procedures Prepared By: Irfan Ilyas

  17. Object Oriented Programming (OOP) • Object is a programming unit having • data (attributes) • methods (operations) • Every object represents some physical object in the real life situation (being programmed) • Every object in a program is created from its Class. • Programmers write Class code for every needed object (class) • Main program is just creating objects and make use of their functionalities Prepared By: Irfan Ilyas

  18. Client_Bill Main Program ClientNameRegularHoursOvertimeHoursRegularRateOvertimeRate Client_Bill object for Client A computeClientBill( TimeCardRecords )printBill( ) Client_Bill object for Client B Example: Advantage Advertising Attributes Methods A class for client bill object Prepared By: Irfan Ilyas

  19. Example: Advantage Advertising Psuedo code for the main program (using Client_Bill Objects) START PROGRAM Create object bill_for_clientA from class Client_Billbill_for_clientA = new Client_Bill() Setting client attributes bill_for_clientA.clientName= “ClientA” bill_for_clientA.RegularRates=100 …… Calling object method for computing the billbill_for_clientA.computeClientBill ( timecardRecords )Calling object method for printing the bill bill_for_clientA.printClientBill ()END PROGRAM Prepared By: Irfan Ilyas

  20. Benefits of OOP • Maximize Code Reusability • Pre-written class codes can be used in any program development • New classes can be derived from pre-written classes with some added functionalities [Inheritance] • Example: Car class can be used for deriving more specific car classes Toyota, Lexus, Mercedes etc. • Simplify Program Writing • Users of an object do not need to know the exact mechanism of any of the object functionalities [Encapsulation] • Easier for the programmers to change the functionality mechanism any time without asking users to change their programs Prepared By: Irfan Ilyas

  21. …Benefits of OOP • Context driven method calls • Some methods look similar in interface and semantics but implemented differently for different objects [Polymorphism] • User doesn’t need to worry about the mechanism • Example: • print method in Client_Bill class • For two different types of client bills (clilent_printed_bill & client_onscreen_bill), the methods print does the same (semantically), however using different mechanism Prepared By: Irfan Ilyas

  22. Introducing Visual Basic for Applications • Visual Basic for Applications (VBA) is the language for building applications with Microsoft office products • VBA is an Object Based Language (not fully object Oriented) • It doesn’t allow you to use inheritance & polymorphism features • Encapsulation feature can be used to some extent. • VBA allows to program already existing objects in different Microsoft Applications Prepared By: Irfan Ilyas

  23. …Introducing Visual Basic for Applications • VBA code helps in integrating the use of different objects (tables, queries, forms etc.) • Produces the effect of a completely customized application Prepared By: Irfan Ilyas

  24. An Example Microsoft Access Database Tables -tblStudent -tblCourse -tblGradesQueriesForms -frmStudentManagement -frmCourseManagement -frmStudentGrades User needs to use database objects interactively (using the command interface available in Access) A Microsoft Access Database (college.mdb) Prepared By: Irfan Ilyas

  25. An Example Microsoft Access Application Users use all objects in an integrated fashion College.mdb Database Objects Prepared By: Irfan Ilyas

  26. VBA in Microsoft Access Environment • Microsoft Access provides an event driven programming environment • An event is a specific action that occurs on (or with) a certain Access object. • Every object in Microsoft Access has a series of events defined. • Command Button Events • Click, DblClick, GotFocus, LostFocus, MouseMove, MouseDown, MouseUp • Form Events • Load, LostFocus, MouseDown, MouseUp, OnConnect, OnDiscount etc. • And many others Prepared By: Irfan Ilyas

  27. Event Driven Programming • An event may come into action (initiated/ triggered) because of • a user action (clicking, pressing a key, changing data etc.) • A time value reached (timing events) • A consequence of another event • Programmers are allowed to write a series of actions (VBA code/ Macro commands) in response to any event. Prepared By: Irfan Ilyas

  28. Mouse Click Event Happens Private Sub Command5_Click() MsgBox "Command Button Works OK" End Sub Go to the event chart of the command button • Event Chart for a command button object • Click event has a VBA Procedure attached to it. Run the procedure attached to it. Program Output An Example Event Driven Program Prepared By: Irfan Ilyas

  29. Main components of VBA Programming • Writing Procedures • VBA statements are written in form of procedures • A procedure is a series of VBA statements • A procedure may be • attached to any objects event (event procedure) Or • written separately (without linking it to any object) • Syntax: Sub procedure_name( ) statement 1 statement 2 : : End Sub Prepared By: Irfan Ilyas

  30. ….Main components of VBA Programming • What to write in VBA Procedures? • Data declaration statements • Syntax: • Dim variable_name As data_type_in_VBA • Example: • Dim X As Integer • Calling Microsoft Access standard Procedures\ Functions (e.g. MsgBox) • Syntax: • MsgBox(prompt[, buttons] [, title] [, helpfile, context]) • Example: • MsgBox(“My First VBA Program”, vbOK, “Test Message”) Prepared By: Irfan Ilyas

  31. ….Main components of VBA Programming • ..What to write in VBA Procedures? • Using Microsoft Access objects • Setting attributes/ calling methods from Microsoft Access Objects • Syntax: • ObjectName.attribute_name = <new value> • ObjectName.method_name [arguments] • Example: • DoCmd.OpenForm frmStudents • Forms!frmStudents.Caption = “New Caption” • Me.Caption = “Changed Caption” Prepared By: Irfan Ilyas

  32. ….Main components of VBA Programming • ..What to write in VBA Procedures? • Using VBA Control Structures • Selection Structure If condition Then Statement(s) [Else Statement(s)] End If • Example: If value = 0 Then AlertLabel.ForeColor = "Red" AlertLabel.Font.Bold = True AlertLabel.Font.Italic = True End If Prepared By: Irfan Ilyas

  33. ….Main components of VBA Programming • ..What to write in VBA Procedures? • Using VBA Control Structures • Loop Structure • Example: Prepared By: Irfan Ilyas

  34. Generations of Programming Languages • Occurring in “generations” • Levels • Machine languages to natural languages • Lower level closer to machine language • Higher level closer to human-like language Prepared By: Irfan Ilyas

  35. Generations of Languages • 1st -- Machine languages • 2nd -- Assembly languages • 3rd -- High level procedural languages • 4th -- Problem-Oriented Languages • 5th -- Natural Languages & Visual programming Prepared By: Irfan Ilyas

  36. Prepared By: Irfan Ilyas

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