COBOL Basics

Character set

In hierarchy 'Characters' are the lowest. They cannot divide further.

In COBOL character set consists of following characters:

Characters	Description
A to Z	Alphabets in Upper case
a to z	Alphabets in Lower case
0 to 9	Numeric
+	Plus sign
*	Asterisk
	Space
-	Hyphen or minus
,	Comma
$	Currency sign
.	Period or Decimal point
;	Semicolon
(	Left parenthesis
)	Right parenthesis
“	Quotation marks
>	Greater than
<	Less than
'	Apostrophe
=	Equal sign
:	Colon

Coding sheet in COBOL

• The source program code of COBOL should be written in an acceptable format to the compiler.
• The code of COBOL program is written in coding sheets.
• In every line of coding there are 80 character positions.

The positions of characters are grouped into the following fields:

Position	Field	Description
1 to 6	Column Numbers	1 to 3 is reserved for page number. 4 to 6 is reserved for line numbers.
7	Indicator	It can have (* , - , /). Asterisk(*) indicates comments, Hyphen(-) indicates continuation, Slash (/) indicate form feed.
8 to 11	Area A	All the COBOL divisions, sections, paragraphs and special entries must start in Area A.
12 to 72	Area B	All COBOL statements should start in area B.
73 to 80	Identification Area	It can be used by the programmer as per the need.

Character String

• By merging individual characters, character strings are formed.
• Character string can be comment, literal or COBOL word.
• All the character strings end with separators.
• Comma, space, period, apostrophe, etc. are the frequently used separators.

Comment

• A comment is a character string. It does not affect the execution of the program.
• The comment can be any combination of characters.

Following are the two types of comments:

Comment Line

• Comment line written in any column.
• For the comment line compiler does not check for syntax and treat for documentation.

Comment Entry

• Comment entries are included in the optional paragraph of an identification division.
• These entries are written in Area B i.e the positions from 12 to 72 and programmers use it for reference.

Literal

Literal is a constant which is directly specified in a program with their values.

Following are the types of literals:

a) Alphanumeric Literal

• Alphanumeric literal are enclosed in apostrophe or quotes.
• The starting and the ending literal should be same.
• The length can be up to 160 characters.

For example:

Valid	Invalid
'It is valid'	'It is not valid”
“It is valid”	“It is not valid'
'It doesn' 't invalid'	'It doesn't valid'

b) Numeric Literal

• It is a combination of digits from 0 to 9, + , - or decimal point.
• The length of it is up to 18 characters.
• The rightmost character cannot be a sign.
• Decimal point should not occur at the end.

Valid	Invalid
200	2,00
+15.9	15.
-3.9	3.9-

COBOL Word

• COBOL word is a character string. It can be user defined reserved word.
• The length of COBOL word is up to 30 characters.

User defined

• Naming files, data, paragraph, records, names and sections are the purposes for which user defined words are used.
• While forming the user defined word alphabets, digits and hyphens are allowed.
• COBOL reserved words should not be used as a user defined word.

Reserved words
Reserved words are the predefined words in COBOL.

Following are the various reserved words often used in COBOL:

• Keywords like ADD, MOVE, ACCEPT etc.
• Special character words like *, +, - , >=, etc.
• Figurative constants are constant values like SPACE, ZERO, etc.

Following are the constant values of figurative constant:

• HIGH-VALUES
• LOW-VALUES
• QUOTES
• ZERO/ZEROES
• SPACES
• ALL literal