Wednesday 19 October 2016

Chapter 13 : Computer Programs and Programming Languages

Computer Programs and Programming Languages

  • A computer program is a series of instructions that directs a computer to perform tasks. Created by a programmer using a programming language.
Low-Level Languages

  • Machine language is the first generation of programming languages.
  • Only language the computer directly recognizes.
  • Assembly language is the second generation of programming languages.
  • A source program contains the code to be converted to machine language.
Procedural language

  • In a procedural language, the programmer writes instructions that tell the computer what to accomplish and how to do it. A compiler translate an entire program before executing it. An interpreter converts and executes one code statement at a time.
  • The C programming language is used to write many of today's programs.
  • COBOL (COmmon Business-Oriented Language) is designed for business applications, but easy to read because of the English-like statements.
Object-Oriented Programming Languages and Program Development Tools

  • An object-oriented programming (OOP) language allows programmers the ability to reuse and modify existing objects.
  • Other advantages include: Objects can be reused, Work well in a RAD environment, Programmers create applications faster.
  • Java is an object-oriented programming language developed by Sun Microsystems.
  • The Microsoft .NET Framework allows almost any type of program to run on the Internet or an internal business network, as well as computers and mobile devices.
  • C++ is an extension of the C programming language.
  • C# is based on C++ and was developed by Microsoft.
  • F# combines the benefit of an object-oriented language with those of a functional language.
A visual programming language is a language that uses a visual or graphical interface for creating all source code.

  • PowerBuilder is a powerful program development RAD tool.
  • A 4GL (fourth-generation language) is a nonprocedural language that enables users and programmers to access data in a database.
  • An application generator is a program that creates source code or machine code from a specification of the required functionality.
  • A macro is a seriess of statements that instructs an application how to complete a task.
  • The macro are usually created in one of two ways: Record the macro with a macro recorder, Write the macro.
Web Page Development

  • HTML is a special formatting language that programmers use to format documents for display on the Web.
  • XHTML is a markup language that allows Web sites to be displayed more easily on mobile devices.
  • XML allows Webs developers to create customized tags and use predefined tags to display content appropriately on various devices. -WML is a subset of XML and is used to design pages for microbrowsers.
  • Two application of XML are RSS 2.0 and ATOM.
  • Web browsers can execute short programs to add interactive elements to Web pages.
  • Programmers write scripts, applets, servlets, or ActiveX controls using a variety of languages.
  • Web 2.0 allows Web sites to provide a means for users to: Share personal information, Allow users to modify Web site content, Have application software built into the site.
  • Web page authoring software can create sophisticated Web pages that include images, video, audio, animation, and other effects
Multimedia Program Development


  • Multimedia authoring software allows programmers, to combine text, graphics, animation, audio, and video in an interactive presentation.
Program Development

  • Program development consists of a series of steps programmers use to build computer programs.
Step 1 - Analyze Requirements
To initiate program development, programmer: i) review the requirements ii) meets with the system analyst and users iii) identifies input, processing, and output.

Step 2- Design Solution

  • Design solution algorithm
  • In structured design, the programmer typically begins with a general design and moves toward a more detailed design.
  • Programmers use a hierarchy chart to show program modules graphically.
  • With object-oriented (OO) design, the programmer packages the data and the program into a single object.
  • The sequence control structure shows one or more actions following each other in order.
  • The selection control structures tells the program which action to take, based on a certain condition.
  • The repetition control structure enables a program to perform one or more actions repeatedly as long as a certain condition is met.
  • A program flowchart graphically shows the logic in a solution algorithm.
  • Flowcharting software makes it easy to modify and update flowcharts.
  • UML (Unified Modeling Language) has been adopted as a standard notation for object modeling and development.
Step 3 - Validate Design

  • Check for logic errors using test data.
Step 4 - Implement Design
  • Implementation of the design includes using a program development tool that assists the programmer by: i) generating or providing some or all code ii) Writing the code that translates the design into a computer program iii) Creating the user interface.
  • Extreme programming is a strategy where programmers immediately begin coding and testing solutions as soon as requirements are defined.
Step 5 - Test Solution
The goal of program testing is to ensure the program runs correctly and is error free.
  • Errors include syntax errors and logic errors
  • Debugging the program involves removing the bugs
  • A beta is a program that has most or all of its features and functionality implemented.
Step 6 - Document Solution
  • In documenting the solution, the programmer performs two activities: Review the program code and all the documentation.


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