PROGRAMMING LANGUAGES

Almost any type of application you can think of can be programmed in one or more of the many programming languages. Just as we humans speak in many different languages, computers also speak (use) many different languages. We can divide programming languages into three categories: machine languages, assembly languages, and high-level languages.

Machine Languages

A machine language consists of a combination of 0s and 1s that is used to indicate OFF and ON states of electricity. All data and instructions are represented (written) in a binary form. This is the ONLY form the computer is able to understand. Each computer has its own machine language; therefore, a program written for one computer type cannot be transferred to another type of computer system. Writing programs in machine language code is time-consuming and requires the programmer to specify each operation code and the specific location for each piece of data and each instruction.

Assembly Languages

We use assembly languages to avoid having to code directly into machine code (0s and 1s). Assembly languages use symbolic codes called mnemonics to represent operations. For example, the letter A could be used for add, and the letters ST could be used for store. Although assembly languages are more user-oriented than machine languages, they are still quite complex to work with as a programmer. Assembly languages are generally used by systems programmers to design and maintain operating systems and other systems software where speed of operation and conserving storage are more important than programmer time.

High-Level Languages

A whole host of high-level programming languages have been developed to solve one particular class of problems or another. High-level languages were developed to allow you, as a programmer, to work in a language that is close to English or mathematical notation, thus improving overall efficiency and simplifying the communications process between you and the computer. These high-level languages allow us to be more concerned with the problems to be solved rather than with the details of computer operation. Examples of high-level languages include COBOL, FORTRAN, BASIC, Pascal, Ada, and C++.

COBOL.\ COBOL was developed for business applications. It uses everyday English-like statements and is good for handling large data files. COBOL is the acronym for COmmon Business-Oriented Language.

FORTRAN.\ FORTRAN was developed for mathematical and scientific work. It is used by engineers, scientists, statisticians, and others in areas where mathematical operations are most important.

FORTRAN is the acronym for FORmula TRANslator.

BASIC.\ BASIC was designed as a teaching language to help beginning programmers write programs. Therefore, it is a general-purpose, introductory language that is fairly easy to learn and to use. With the increase in the use of microcomputers, BASIC has regained popularity and is available on most microcomputer systems. BASIC is the acronym for Beginner's All-Purpose Symbolic Instruction Code.

PASCAL.\ Pascal is a language designed to teach programming. It is fairly easy to learn; yet it is a more powerful language than BASIC. Although Pascal is not yet a standardized language, it is still used rather extensively on microcomputers. It has greater programming capabilities on small computers than are possible with BASIC. It is used by many colleges and universities. It is named after Blaise Pascal, a mathematician and the inventor of the first mechanical adding machine.

ADA.\ Ada is a modern, general-purpose language designed with the professional programmer in mind. It has many unique features to aid in the implementation of large-scale applications and real-time systems. Its development was initiated by the U.S. Department of Defense (DOD). It is named to honor the achievements of Ada Augusta Byron, Countess of Lovelace, who was a supporter of and collaborator with Charles Babbage, the first person to propose the concept of the modern computer. She suggested using the binary system of storage instead of the decimal system and developed the concept of a loop to execute repetitive instructions. Babbage is known as the father of the computer, and Ada Lovelace is considered the first programmer.

C++.\ C++ is a general-purpose language that works well with microcomputers. It is useful for writing both operating systems and database programs. The programs are portable, which allows them to be run without change on a variety of computers.