1. Computer Programming How Can You Create Your Own Software? Chapter 11

2. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 2 Objectives 1.Understand how computer programming works within the systems development life cycle (SDLC). 2.Understand the basic coding techniques and control structures needed to write a software application. 3.Describe various programming logic, syntax, and run-time errors.

3. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 3 Objectives 4.Understand how programmers implement and maintain software. 5.Identify the various programming language generations and characteristics. 6.Explore the newer Web programming languages and understand how they are used.

4. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 4 A:// Programmer's View of Investigation, Analysis, and Design Systems Investigation –Lay the foundation for a new system –Define the problem/opportunity Systems Analysis –Focus on information and processing –Develop logical specifications Systems Design –Convert logical descriptions –Focus on physical characteristics

5. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 5 Systems Investigation What is client’s request? Questions to ask: Create problem/opportunity statements

6. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 6 Systems Analysis 1.What information will go into the software? 2.How will the software process information? 3.What information will the software generate?

7. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 7 Programmer Modeling Techniques Pseudocode –Outline of necessary steps –Steps called algorithms Program Flowcharts –Plots software’s algorithms –Graphical depiction of detailed steps

8. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 8 Pseudocode Use simple English One command per line Boldface important words Start at top Form modules using spaces

9. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 9 Program Flowcharts

10. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 10 Systems Design Convert logical descriptions into software specifications Know basic software needs –Input –Processing –Output

11. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 11 Input-Process-Output Tables

12. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 12 Making the Grade Section A: // 1.____________ uses English statements to create an outline of an algorithm. 2.An ____________ is a set of specific steps to solve a problem. 3.A _________ is a location in the system’s memory that holds different values in software. 4.Managing information according to software’s logic is _____.

13. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 13 B:// Writing Computer Software Construction phase of SDLC Coding –Explain your algorithm in terms a computer can understand –Write software using a programming language Programming language contain specific rules and words Expresses the logical steps of an algorithm

14. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 14 Software Written in Visual Basic (VB)

15. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 15 Control Structures Sequential execution – code is executed in order it appears Control structures – you specify order in which code is executed 1.Sequence control structures 2.Selection control structures 3.Repetition control structures

16. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 16 Sequence Control Structure Executes software from top to bottom, left to right Enforces sequential execution

17. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 17 Selection Control Structure Uses an existing condition to decide how a computer will execute software Makes a decision based on a condition

18. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 18 Selection Control Structures If-Then-Else Control StructureCase Control Structure

19. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 19 Repetition Control Structure Repeats a series of steps Called iteration control or loop  Do-while  Do-until  For-next

20. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 20 Repetition Control Structures  Do-while control – repeats a portion of code as long as a certain condition exists  Do-until control – repeats a portion of code as long as a certain condition doesn’t exists  For-next control – repeats a portion of code a precise number of times

21. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 21 ISeries Insights Ethics, Security & Privacy Programming Backdoors Backdoor is an undocumented method to gain access to a program or computer Saves time when making fixes Can cause problems –Hackers –Viruses Are backdoors beneficial or too risky?

22. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 22 Making the Grade Section B: // 1. _________ is when you translate your algorithm into a programming language. 2. Programming languages have __________ words for certain purposes. 3. The ___________ structure tests a condition that can result in more than a true or false answer. 4. Repetition control structures are also called __________.

23. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 23 C:// Testing, Implementing, and Maintaining Software Systems Development Life Cycle Phases  Construction - phase #4  Implementation - phase #5  Support - phase #6 Phases correspond to programming steps  Testing  Implementation  Maintenance

24. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 24 Testing Software Debugging  Process of finding errors  Bugs – common name for software errors Types of errors  Syntax errors  Run-time errors  Logic errors

25. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 25 Syntax Errors Mistakes in a software code’s grammar Misspelling a command word Forgetting to close a module

26. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 26 Run-Time Errors Mistakes that occur when you run code –Not displaying a window correctly –Not matching variables in a calculation –Adding a number and a letter is a good example

27. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 27 Logic Errors Check first for errors when you design an algorithm Logic error is a mistake in the way algorithm solves a problem

28. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 28 User Testing Users must test software Acceptance testing - “sign off” that software works correctly

29. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 29 Software Development Environment An application that provides programming tools –Used to debug software –Manages software programs Powerful programming features Rapid application development (RAD) Tool that is used instead of a simple text editor like Notepad

30. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 30 Microsoft VB Development Environment

31. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 31 Case Tools Computer aided software engineering Software applications Tools that help to… Prepare reports Draw program flowcharts Generate software code for prototypes What are prototypes?

32. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 32 Microsoft Visio – CASE Tools

33. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 33 Implementing Software Comments Program manual User manual Why is documentation important?

34. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 34 Maintaining software Software Patches –Small fix to a program problem –Uses a piece of software code Software upgrades –Used when patches are no longer enough –Substantial revision of existing software –Example – MS Office XP is an upgrade to MS Office 2000

35. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 35 Making the Grade Section C: // 1. _________ errors are mistakes in a software code’s grammar. 2. _________ testing involves testing each individual program. 3. A ____________ is a technical manual for programmers. 4. A _____________ is a small fix to a software problem.

36. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 36 D:// Programming Language Machine language  Machine-dependent & low level language  Uses binary code Assembly language  Machine-dependent & low level language  Uses word abbreviations

37. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 37 Assembly Language Program

38. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 38 Programming Languages Third Generation Language  Machine-independent & high-level language  Uses human words and symbols  Procedural language  Examples  COBOL  C++  Fortran  Java

39. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 39 Programming Languages Fourth Generation Language  Machine-independent  High-level language  Non-procedural  Uses human words and symbols  Example - SQL

40. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 40 Programming Language Characteristics Compiled –Compiler –Source code & object code Interpreted Scripted –Interpreted language that works with another application –Visual Basic for Applications (VBA)

41. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 41 VBA in Microsoft Excel

42. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 42 Object-Oriented Programming Objects –Procedures –Object-oriented programming (OOP) Object instance Event driven

43. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 43 Programming Languages

44. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 44 Making the Grade Section D: // 1. A _____________ language works only on a specific computer system. 2. A _______ is a utility program that converts assembly language into machine language. 3. A ___________ translates a high-level programming language into machine language. 4. A ________ is an item that contains information and procedures.

45. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 45 E:// Web Programming Markup language HTML – Hypertext Markup Language XML – eXtensible Markup Language XHTML – eXtensible HTML Syntax A set of rules to follow Used by markup languages to instruct Web browsers

46. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 46 Practically Speaking Language Translators Software that can translate Web pages, e-mail letters, reports, manuals, and books into another language Some Web sites will translate text for free Be wary – some phrases don't translate well

47. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 47 Client-Side Web Programming Languages Dynamic HTML (DHTML) –Combines CSS, JavaScript, specific tag extensions, and other markup languages –Brings high interactivity to Web sites VBScript –Similar to JavaScript –Only Microsoft's Internet Explorer Web browser can use it

48. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 48 Server-Side Web Programming Languages Need Web servers to run certain applications Uses Web server resources to… –Retrieve information –Process information –Output customized Web pages Used for advanced applications and tasks

49. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 49 Making the Grade Section E: // 1. ________ combines HTML with XML. 2. _________ Web programming languages use Web browser resources to add interactivity and new functions to Web pages. 3. ___________ is an interpreted scripting language based on Visual Basic. 4. _____________ programming user Web server resources.

50. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 50 F:// “Key” Key Terms algorithm (p. 11.4) backdoor (p. 11.12) bug (p. 11.13) CASE (p. 11.16) debugging (p.11.13) documentation (p.11.16) object code (p. 11.21) program flowchart (p. 11.7) pseudocode (p. 11.4) source code (p. 11.21)

51. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 51 Frequently Asked Questions I know HTML. Can I be called a programmer? What steps should a programmer take to write software? What is pseudcode? How is it used? What is an algorithm? What software should a programmer use to create an application?

52. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 52 FAQs cont. Are repetition-control structures like program loops? What are CASE Tools? What is the difference between a patch and an upgrade? Is Visual Basic 3GL or 4GL? What's the difference between a Web programmer and a Web developer?

53. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 53 Hands On Projects E-Commerce Did you know that you can get your credit history online? Find five sites that let you order a copy of your credit history. –Is the service free or is there a charge? –How many months can you use the service? –Can you get reports from more than one credit agency?

54. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 54 Hands On Projects On the Web You don't have to be a programmer to enhance your web site and make it more attractive. Find sites that offer free code to add to your HTML code. What programs are available? How useful is this code? If you have already created a Web page, try inserting some of these programs to see how they work.

55. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 55 Hands On Projects Ethics, Security, & Privacy There is a story of a programmer who created a payroll system to self-destruct if his name was not included among the weekly pay checks. If you were a manager, what would you do to make sure that you received good code, service, and support from the individuals creating software for your business?

56. McGraw-Hill/Irwin Copyright 2002 by the McGraw-Hill Companies, Inc. All rights reserved. 11 - 56 Hands On Projects Group Activities Not all school registration systems are perfect. What about yours? Could it use improvement? Work with your group to identify a problem or opportunity for class registration. Analyze the situation, create a problem/opportunity statement, and design the pseudocode and flowchart.