Let's assume that we have studied the problem, designed a \
logical plan (our flowchart or pseudocode), and are now ready \
to write the program instructions. The process of writing pro- j
gram instructions is called coding. The instructions will be writ-.
ten 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 ■ v
any old way. The instructions must be written according to a set!
of rules. These rules are the foundation of a programming Ian- j
guage. 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 j
languages have improved throughout the years, just as comput- I.
er hardware has improved. They have progressed from machine- \
151_______________________ Unit 11. 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
COBOL was the most widely used business-oriented programming language. Its name is an acronym for Common lisi-ncss-Oriented Zanguage. 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 sentencelike 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.
FORTRAN IV
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
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
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used. COBOL and FORTRAN have been available for a longer period of time than PL/I, and many more users work with those languages.
9. ,
.
1. What is the process of writing instructions called? 2. What is a code? 3. How must instructions be written? 4. What is the foundation of any programming language? 5. How was the development of programming languages progressing throughout the years? 6. What are the most common problem-oriented languages? 7. What is COBOL? 8. What functions was COBOL designed for? 9. What does FORTRAN serve for? 10. What capabilities has PL/I?
10.
:
; -; ; , ; ; ; ; ; - ; - ; ; ; ; - ; ; ; ; ; ; ; ; .
11. 1 2 ,
:
Nouns: command; line; characteristic; form; evolution; enumeration; mistake; method; character; manual (instruction); consumption; storage; basics; abbreviation; interpretation; correlation; possibility.
Verbs: include; inform; process; protect; apply; permit; stress; suppose; learn; make up; write; key; explain; define; perfect; advance; decide; execute; demand.
153 Unit 11. Computer Programming
Adjectives: full; incorrect; usual; necessary; accessible; required; considerable; floppy; possible.
