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.

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.
• Most program development tools are IDEs

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.Features include : CLR , Classes

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.

Visual Studio is Microsoft’s suite of program development tools

• Visual Basic is based on the BASIC programming language
• Visual C++ is based on C++
• Visual C# combines the programming elements of C++ with an easier, rapid-development environment

A visual programming language is a language that uses a visual or graphical interface for creating all source code.

Borland’s Delphi is a powerful program development tool that is ideal for building large-scale enterprise and Web applications in a RAD environment

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 series of statements that instructs an application how to complete a task.

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.

Dynamic HTML  (DHTML) allows Web developers to include more graphical interest and

interactivity

Ruby on Rails (RoR) provides technologies for developing object-oriented, database-driven Websites

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

• Dreamweaver 
• Expression web 
• Flash
• Sharepoint designer

Multimedia Program Development

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

• toolbox
• Director 

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

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: 

•  generating or providing some or all code 
• Writing the code that translates the design into a computer program 
• Creating the user interface.

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
• Review all the documentation.