What Is a Programming Language

Simply put, a programming language is a very special and very restricted language that is understood by the computer at some level. We can roughly divide programming languages into three groups, based on the purpose of the language:

• Languages designed to manipulate the computer at a low level, that is, to manipulate the operating system (Windows or DOS) or even the hardware itself, are called low-level languages. An example is assembly language.

• Languages designed to create standalone applications, such as Microsoft Excel, are highlevel languages. Examples are BASIC, COBOL, FORTRAN, Pascal, C, C++, and Visual Basic.

• Languages that are designed to manipulate an application program, such as Microsoft Excel, are application-level languages. Examples are Excel VBA, Word VBA, and PowerPoint VBA.

Those terms are not set in concrete and may be used differently by others. However, no one would disagree that some languages are intended to be used at a lower level than others.

The computer world is full of programming languages—hundreds of them. In some cases, languages are developed for specific computers. In other cases, languages are developed for specific types of applications. Table 2-1 gives some examples of programming languages and their general purposes.

Table 2-1. Some Programming Languages

Language

General Purpose

ALGOL

An attempt to design a universal language

BASIC

A simple, easy-to-learn language designed for beginners

C, C++

A very powerful languages with excellent speed and control over the computer

COBOL

A language for business programming

FORTRAN

A language for scientific programming and number crunching

Lisp

A language for list processing (used in artificial intelligence)

Pascal

A language to teach students how to program "correctly"

SIMULA

A language for simulating (or modeling) physical phenomena

Smalltalk

A language for object-oriented programming

Visual Basic

A version of BASIC designed for creating Windows applications

Visual C++

A version of C++ designed for creating Windows applications

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Programming languages vary quite a bit in their syntax. Some languages are much easier to read than others (as are spoken languages). As a very simple example, Table 2-2 shows some ways that different programming languages assign a value (in this case, 5) to a variable named X. Notice the variation even in this simple task.

Table 2-2. Assignment in Various Languages

Language

Assignment Statement

APL

X <- 5

BASIC

LET X = 5 or X = 5

BETA

5 -> X

C, C++

X = 5;

COBOL

MOVE 5 TO X

FORTRAN

X = 5

J

X =. 5

LISP

(SETQ X 5)

Pascal

X := 5

Visual Basic

X = 5

If you're interested in how Visual Basic compares with some of the other major programming languages, Appendix F contains a short description of several languages, along with some programming examples.

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