Let’s
assume that we have studied the problem, designed a logical plan (our
flowchart or pseudo code), and are now ready to write the program
instructions. The process of writing program instructions is called coding.
The instructions will be written on a form called a coding form. The
instructions we write will be recorded in a machine-readable form using a
keypunch, key-to-tape, or key-to-disk, or entered directly into computer;
memory through a terminal keyboard.
The computer cannot understand instructions written in just any old way. The
instructions must be written according to a set of rules. These rules are
the foundation of a programming language. A programming language must convey
the logical steps of the program plan in such a way that the control unit of
the CPU can interpret and follow the instructions. Programming languages
have improved throughout the years, just as computer hardware has improved.
They have progressed from machine.
Computer Programming oriented languages that use strings of binary Is and 0s
to problem-oriented languages that use common mathematical and/or English
terms.
There are over 200 problem-oriented languages. The most common of them are
COBOL, FORTRAN, PL/I, RPG, BASIC, PASCAL.
COBOL
was the most widely used business-oriented programming language. Its name is
an acronym for Common Business-Oriented Language. COBOL was designed to
solve problems that are oriented toward data handling and input-output
operations. Of course, COBOL can perform arithmetic operations as well, but
its greatest flexibility is in data handling. COBOL also was designed as a
self-documenting language. Self-documenting languages are those that do not
require a great deal of explanation in order to be understood by someone
reading the program instructions. The self-documenting aspect of COBOL is
made possible by its sentence like structure and the very generous maximum
symbolic field-name length of 30 characters. With a field-name length of up
to 30 characters, the name can clearly identify the field and its purpose.
The FORTRAN
IV
language is oriented toward solving problems of a mathematical nature. The
name FORTRAN comes from the combination of the words formula
translation. The version of FORTRAN IV has been designed as
algebra-based programming language. Any formula or those mathematical
relationships that can be expressed algebraically can easily be expressed as
a FORTRAN instruction. FORTRAN is the most commonly used language for
scientific applications.
PL/I
stands for programming language I. It was designed as a general-purpose
language incorporating features similar to COBOL for data handling
instructions and features similar to FORTRAN for mathematical instructions.
PL/I is much more than a combination of the good features of both COBOL and
FORTRAN, as it has many capabilities that are unique. Yet, although PL/I is
one of the most versatile and the most powerful of the programming
languages, it is not the most commonly used. COBOL and FORTRAN have been
available for a longer period of time than PL/I, and many more users work
with those languages. |