Chapter 10


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  • In this behind-the-scenes chapter, we explore the stages of program development and survey the most popular programming languages.
  • Chapter 10

    1. 1. Technology in Action <ul><li>Chapter 10 </li></ul><ul><li>Behind the Scenes: Software Programming </li></ul>
    2. 2. Information Systems <ul><li>System </li></ul><ul><ul><li>A collection of pieces working together to achieve a common goal </li></ul></ul><ul><li>An information system includes </li></ul><ul><ul><li>Data </li></ul></ul><ul><ul><li>People </li></ul></ul><ul><ul><li>Procedures </li></ul></ul><ul><ul><li>Hardware/Software </li></ul></ul><ul><li>System development life cycle (SDLC) </li></ul><ul><ul><li>An organized process (or set of steps) used to develop systems in an orderly fashion </li></ul></ul>NB
    3. 3. System Development Life Cycle Problem/ Opportunity Identification Analysis Design Development & Documentation Testing & Installation Maintenance & Evaluation System Development Life Cycle NB
    4. 4. Design <ul><li>A detailed plan for programmers is developed </li></ul><ul><li>Flowcharts and data-flow diagrams are used for the current and proposed system </li></ul><ul><li>Document the design </li></ul>Data-flow diagram Flowchart NB
    5. 5. Development & Documentation <ul><li>Actual programming takes place </li></ul><ul><li>First phase of the program development life cycle (PDLC) </li></ul><ul><li>Development is documented </li></ul><ul><li>User documentation is created </li></ul>
    6. 6. The Life Cycle of a Program <ul><li>Programming is the process of translating a task into a series of commands a computer will use to perform that task </li></ul><ul><li>Programming involves: </li></ul><ul><ul><li>Identifying the parts of a task the computer can perform </li></ul></ul><ul><ul><li>Describing tasks in a specific and complete manner </li></ul></ul><ul><ul><li>Translating the tasks into a language that is understood by the computer’s CPU </li></ul></ul>NB
    7. 7. Program Development Life Cycle Step 5 Finishing the Project Step 4 Debugging Step 3 Coding Step 2 Making a Plan Step 1 Describing the Problem NB
    8. 8. Step 1 : Describing the Problem <ul><li>The problem statement is: </li></ul><ul><ul><li>The starting point of programming </li></ul></ul><ul><ul><li>A description of tasks the program is to accomplish </li></ul></ul><ul><ul><li>How the program will execute the tasks </li></ul></ul><ul><ul><li>Created through interaction between the programmer and the user </li></ul></ul><ul><li>The program statement includes error handling and a testing plan </li></ul>NB
    9. 9. Step 2: AlgorithmS <ul><li>Algorithm development: </li></ul><ul><ul><li>A set of specific, sequential steps that describe what the computer program must do </li></ul></ul><ul><ul><li>Complex algorithms include decision points: </li></ul></ul><ul><ul><ul><li>Binary (yes/no) </li></ul></ul></ul><ul><ul><ul><li>Loop (repeating actions) </li></ul></ul></ul><ul><ul><li>Visual tools used to track algorithm and decision points: </li></ul></ul>Head off to cafe Buy textbook Go to accounting lecture Yes No No No Yes Yes Wake Up Check wallet for $ Do I have > $80 Go get gas Did I get $80 from the ATM? Do I have my credit card? Go to the ATM for cash NB
    10. 10. Flowchart and Pseudocode Underlined words are information items that appear repeatedly in the algorithm. 1. Ask the user how many hours they worked today 2. If the number of hours worked < = 8, compute total pay without overtime otherwise, compute total pay with overtime pay 3. Print total pay Bold terms show actions that are common in programming, such as reading data, making decisions, printing, and so on. Flowchart Pseudocode NB
    11. 11. Top-Down Design <ul><li>Problem is divided into a series of high-level tasks </li></ul><ul><li>Detailed subtasks are created from high-level tasks </li></ul>NB
    12. 12. Object-Oriented Analysis <ul><li>Object-oriented analysis </li></ul><ul><li>Classes (categories of inputs) are identified </li></ul><ul><li>Classes are defined by information (data) and actions (methods or behaviors) </li></ul><ul><li>Objects are defined by their class, data, and behavior </li></ul><ul><li>Interaction between classes is determined </li></ul><ul><li>Existing classes can be used for other projects </li></ul>NB
    13. 13. Step 3: Coding <ul><li>Coding is translating an algorithm into a programming language </li></ul><ul><li>Generations of programming languages </li></ul>NB
    14. 14. Compilation <ul><li>Compilation is the process of converting code into machine language </li></ul><ul><li>Compiler reads the source code and translates it into machine language </li></ul><ul><li>After compilation, programmers have an executable program </li></ul>NB
    15. 15. Interpreter <ul><li>Interpreter translates source code into a line by line intermediate form </li></ul><ul><li>Each line is executed before the next line is compiled </li></ul><ul><li>Programmers do not have to wait for the entire program to be recompiled each time they make a change. </li></ul><ul><li>Programmers can immediately see the results of changes as they are making them in the code. </li></ul>NB
    16. 16. Step 4: Debugging <ul><li>Running a program to find errors is known as debugging </li></ul><ul><li>Sample inputs are used to determine runtime (logic) errors </li></ul><ul><li>Debugger: Tool that helps programmers locate runtime errors </li></ul>NB
    17. 17. Step 5: Finishing the Project <ul><li>Users test the program (internal testing) </li></ul><ul><li>Beta version released: </li></ul><ul><ul><li>Information collected about errors before final revision </li></ul></ul><ul><li>Software updates (service packs): </li></ul><ul><ul><li>Problems found after commercial release </li></ul></ul><ul><li>Documentation created: </li></ul><ul><ul><li>User manuals </li></ul></ul><ul><ul><li>User training </li></ul></ul>NB
    18. 18. Programming Languages <ul><li>Selecting the right language: </li></ul><ul><ul><li>Space available </li></ul></ul><ul><ul><li>Speed required </li></ul></ul><ul><ul><li>Organizational resources available </li></ul></ul><ul><ul><li>Type of target application </li></ul></ul>Visual Basic C / C++ Java HTML JavaScript VBScript ASP / JSP Flash / XML NB
    19. 19. Visual Basic <ul><li>Used to build Windows applications </li></ul><ul><li>Object-oriented language </li></ul><ul><li>Visual Basic 2005 is the current version </li></ul>Sample Visual Basic NB
    20. 20. C and C++ <ul><li>C </li></ul><ul><ul><li>Developed for system programmers </li></ul></ul><ul><ul><li>Combines high and low level programming features </li></ul></ul><ul><ul><li>Modern operating systems written in C </li></ul></ul><ul><li>C++ </li></ul><ul><ul><li>Uses the same features as C </li></ul></ul><ul><ul><li>Includes object-oriented design </li></ul></ul>Sample C Sample C++ NB
    21. 21. Java <ul><li>Object-oriented features </li></ul><ul><li>Large set of existing classes </li></ul><ul><li>Architecture neutral </li></ul><ul><li>Java applets: Small Java-based programs </li></ul>NB
    22. 22. Web Applications <ul><li>HTML/XHTML </li></ul><ul><ul><li>Hypertext Markup Language/Extensible Hypertext Markup Language </li></ul></ul><ul><ul><li>Not a true programming language </li></ul></ul><ul><ul><li>Uses special symbols (tags) to control how Web pages are viewed </li></ul></ul><ul><li>Extensible Markup Language (XML) </li></ul><ul><ul><li>Enables computers to efficiently transfer information between Web sites </li></ul></ul>NB
    23. 23. Web Applications <ul><li>JavaScript </li></ul><ul><ul><li>Used to make Web pages more visually appealing and interactive </li></ul></ul><ul><li>VBScript </li></ul><ul><ul><li>A subset of Visual Basic </li></ul></ul><ul><ul><li>Used to add interactivity to Web pages </li></ul></ul><ul><li>PHP </li></ul><ul><ul><li>Another scripting language gaining popularity </li></ul></ul><ul><li>Dynamic Decision Making </li></ul><ul><ul><li>Web page has the ability to display content based on user choices </li></ul></ul>NB
    24. 24. Web Applications <ul><li>Active Server Pages (ASP) and Java Server Pages (JSP) </li></ul><ul><ul><li>Adds interactivity capabilities to Web pages </li></ul></ul><ul><ul><li>Translates user information into a request for more information from a company’s computer </li></ul></ul><ul><li>Flash </li></ul><ul><ul><li>Enables elaborate animations to be created for Web pages </li></ul></ul>NB