1. Programming in COBOL-85 For IBM Mainframe System 390
Jyothi Sridhar Kini
E&R, Infosys
Mail-id:
Phone:

2. Course Plan Day 1: Introduction to COBOL
Day 2: Cobol Language constructs
Day 3: Sequential File Handling
Day 4: Index sequential file handling, COPY, CALL
Day 5,6,7: Working on project

3. Pre-requisites Programming Fundamentals.
MVS Operating system and its subsystem TSO.
Job Control Language to submit jobs to MVS.
Navigating through ISPF.

4. Topics beyond the scope
Report writer feature of COBOL

5. Any Time reference IBM manuals
References
TITLE
AUTHOR
PUBLISHER
COBOL Programming
M.K.Roy and D. Ghosh Dastidar
Tata McGraw Hill
Nancy Stern and Robert Stern
John Wiley & Sons Inc
Programming with Structured COBOL
Newcomer and Lawrence
McGraw Hill Books
(Schaum Series)
Any Time reference IBM manuals

6. Agenda for Day 1 Evolution and Features of COBOL.
General Coding and Format rules.
Language Fundamentals.
Input and Output verbs.
Arithmetic verbs.
Design and development of simple COBOL programs

7. History of COBOL Early years. ANS Versions of COBOL.
Future of COBOL

8. History of COBOL
1960 – COBOL (Common Business Oriented Language) initial specifications presented by CODASYL (Conference on Data System Languages)
1964 – revised to make COBOL more flexible
1968 – ANSI (American National Standards Institute) developed American National Standard (ANS) COBOL
Standardized form
Attempted to overcome incompatibilities of different versions of COBOL
1974 – ANSI published revised version of (ANS) COBOL
Business applications needed to manipulate character as well as numeric data
String operations added

9. 1985 – ANSI published another revised version of COBOL
History of COBOL
1985 – ANSI published another revised version of COBOL
Designed to take advantage of structured programming techniques
Logic errors reduced with END statements
Case statement reduced nested IFs
Less English-like
Maintained readability and business orientation
Compatible with previous versions

10. COBOL
COBOL is an acronym which stands for COmmon Business Oriented Language.
The name indicates the target area of COBOL applications.
COBOL is used for developing business, typically file-oriented, applications.
It is not designed for writing systems programs. You would not develop an operating system or a compiler using COBOL.
COBOL is one of the oldest computer languages in use (it was developed in late 1950s).

11. CODSYL

12. Nature of COBOL Business Oriented Language. Standard Language.
Robust Language.
Structured Programming Language.
English-like Language.

13. Structure of a COBOL program
SENTENCES
PROGRAM
STATEMENTS
DIVISIONS
RESERVED
WORDS
USER DEFINED
WORDS
SECTIONS
PARAGRAPHS
CHARACTERS

14. COBOL Character set Alphabets (Both upper and lower case)
Digits (0 to 9)
Special characters b * / = $ , ; “ ‘ < > ( )

15. The COBOL DIVISIONs
DIVISIONS are used to identify the principal components of the program text. There are four DIVISIONS in all.
IDENTIFICATION DIVISION.
ENVIRONMENT DIVISION. // Optional
DATA DIVISION // Optional
PROCEDURE DIVISION.

16. IDENTIFICATION DIVISION
The purpose of the IDENTIFICATION DIVISION is to provide information about the program to the programmer and to the compiler.
Most of the entries in the IDENTIFICATION DIVISION are directed at the programmer and are treated by the compiler as comments.

17. IDENTIFICATION DIVISION...
An exception to this is the PROGRAM-ID clause. Every COBOL program must have a PROGRAM-ID. It is used to enable the compiler to identify the program.
There are several other informational paragraphs in the IDENTIFICATION DIVISION but we will ignore them for the moment.

18. IDENTIFICATION DIVISION...
The IDENTIFICATION DIVISION has the following structure IDENTIFICATION DIVISION. PROGRAM-ID. PGM-NAME. [AUTHOR. YourName.]
IDENTIFICATION DIVISION.
PROGRAM-ID. FIRSTPGM.
AUTHOR. Michael Coughlan.

19. IDENTIFICATION DIVISION...
The keywords IDENTIFICATION DIVISION represent the division header and signal the commencement of the program text.
The paragraph name PROGRAM-ID is a keyword. It must be specified immediately after the division header.
The program name can be up to 8 characters long on MF(30 in case of windows).

20. IDENTIFICATION DIVISION...
Is used to identify the program to the computer.
Is the least significant DIVISION of a COBOL program.
IDENTIFICATION DIVISION.
PROGRAM-ID. Member-name. ( Max 8 chars, letters & digits only )
AUTHOR. / Optional entry
INSTALLATION. / Optional entry
DATE-WRITTEN. / Optional entry
DATE-COMPILED. / Optional entry

21. ENVIRONMENT DIVISION
The ENVIRONMENT DIVISION is totally optional unless you want to use files / specify special devices to the compiler in your program.
Is used to indicate the Specific Computers used to develop and execute the program.
The general format of ED is
ENVIRONMENT DIVISION.
CONFIGURATION SECTION.
SOURCE-COMPUTER. VAX-6410.
OBJECT-COMPUTER. IBM-ES9000.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT EMPL-FILE ASSIGN TO DISC.
...

22. The DATA DIVISION
The DATA DIVISION is used to describe most of the data that a program processes.
The DATA DIVISION has two main sections-
FILE SECTION.
WORKING-STORAGE SECTION.
The FILE SECTION is used to describe most of the data that is sent to, or comes from, the computer’s peripherals.
The WORKING-STORAGE SECTION is used to describe the general variables used in the program.

23. DATA DIVISION
Is used to describe the structure of the fields, records, files and temporary variables used for calculations.
DATA DIVISION / Optional entry
FILE SECTION.
FD filename
SD sortfile
WORKING-STORAGE SECTION.

24. PROCEDURE DIVISION
Is the most significant DIVISION of a COBOL program.
Includes statements and sentences necessary for reading input, processing it and writing the output. These are the instructions that are executed by the computer at the RUN TIME.

25. PROCEDURE DIVISION…
The PROCEDURE DIVISION is where all the data described in the DATA DIVISION is processed and produced desired results. It is here that the programmer describes his algorithm.
The PROCEDURE DIVISION is hierarchical in structure and consists of Sections, Paragraphs, Sentences and Statements.

26. PROCEDURE DIVISION...
Only the Section is optional. There must be at least one paragraph, sentence and statement in the PROCEDURE DIVISION .
In the PROCEDURE DIVISION, paragraph and section names are chosen by the programmer.
The names used should reflect the processing being done in the paragraph or section.

27. Sections
A SECTION is a block of code made up of one or more paragraphs.
A SECTION begins with the section-name and ends where next section name is encountered or where the program text ends.
A SECTION name consists of a name devised by the programmer or defined by the language followed by the word SECTION followed by a full stop.
U0000-SELECT-USER-RECORDS SECTION.
FILE SECTION.

28. Paragraphs Each section consists of one or more paragraphs.
A PARAGRAPH is a block of code made up of one or more sentences.
A PARAGRAPH begins with the paragraph-name and ends with the next paragraph or section name or the end of the program text.
The paragraph-name consists of a name devised by the programmer or defined by the language followed by a full stop.
P0000-PRINT-FINAL-TOTALS.
PROGRAM-ID.

29. Sentences and Statements
A PARAGRAPH consists of one or more sentences.
A SENTENCE consists of one or more statements and is terminated by a full stop.
MOVE .21 TO VAT-RATE COMPUTE VAT-AMOUNT = PRODUCT-COST * VAT-RATE.
DISPLAY "Enter Name " WITH NO ADVANCING ACCEPT STUDENT-NAME DISPLAY "Name Entered was " STUDENT-NAME.
A STATEMENT consists of a COBOL verb and an operand or operands.
SUBTRACT T-TAX FROM GROSS-PAY GIVING NET-PAY
READ STUDENT-FILE AT END SET END-OF-FILE TO TRUE END-READ

30. First COBOL program IDENTIFICATION DIVISION. PROGRAM-ID.FIRSTPGM.
AUTHOR. Michael Coughlan.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-NUM PIC 9(001) VALUE ZEROS.
01 WS-NUM PIC 9(001) VALUE ZEROS.
01 WS-RESULT PIC 9(002) VALUE ZEROS.
PROCEDURE DIVISION.
A0000-MAIN-PARA.
ACCEPT WS-NUM-1
ACCEPT WS-NUM-2
MULTIPLY WS-NUM-1 BY WS-NUM-2 GIVING
WS-RESULT-1
DISPLAY "Result is = ", WS-RESULT-1
STOP RUN .

31. The minimum COBOL program
IDENTIFICATION DIVISION.
PROGRAM-ID. SMALLPGM.
PROCEDURE DIVISION.
A0000-DISPLAY-PARA.
DISPLAY "I did it."
STOP RUN .
What is the model we have used to describe the
COBOL program structure?
TOP-DOWN

32. COBOL coding rules
Almost all COBOL compilers treat a line of COBOL code as if it contained two distinct areas. These are known as; Area A and Area B
When a COBOL compiler recognizes these two areas, all division, section, paragraph names, FD entries and 01 level entries must start in Area A. All other sentences/statements must start in Area B.
Area A is four characters wide and is followed by Area B.

33. COBOL coding rules...
In some COBOL compilers these coding restrictions are removed.
For example In Microfocus COBOL compiler directive $ SET SOURCEFORMAT"FREE" frees us from all formatting restrictions.
$ SET SOURCEFORMAT"FREE"
IDENTIFICATION DIVISION.
PROGRAM-ID. ProgramFragment.
* This is a comment. It starts
* with an asterisk in column 1

34. COBOL coding sheet Column numbers 1 2 3 4 5 6 7 8 9 10 11 12 72 80 *
Area A
Area B I D E N T F C A O R - /

35. COBOL coding rules
Each line is considered to be made up of 80 columns.
Columns 1 to 6 are reserved for line numbers.
Column 7 is an indicator column and has special meaning to the compiler. Asterisk ( * ) indicates comments Hyphen ( - ) indicates continuation Slash ( / ) indicates form feed

36. COBOL coding rules
Columns 8 to 11 are called Area A. All COBOL DIVISIONs, SECTIONs, paragraphs and some special entries must begin in Area A.
Columns 12 to 72 are called Area B. All COBOL statements must begin in Area B.
Columns 73 to 80 are identification area.

37. COBOL data description
COBOL uses what could be described as a “declaration by example” strategy.
In effect, the programmer provides the system with an example, or template, or PICTURE of what the data item looks like.
From the “picture” the system derives the information necessary to allocate it.

38. Basic data types Alphabetic Numeric Alphanumeric Edited numeric
Edited alphanumeric

39. Literals
Literals are symbols whose value does not change in a program.
There are 3 types of literals namely (1) Numeric literals (2) Non-numeric literals (3) Figurative constants.

40. Literals Numeric literals Are formed using digits only.
May include a sign which must be the extreme left character.
There must not be any blank between the sign and the first digit.
May include a decimal point which can not be the right most character.
Can have at most 18 digits.

41. Literals Non-numeric literals Are used display headings or messages.
Are a sequence of characters (except quotes) from the COBOL character set enclosed within quotes.
May contain up to 160 characters including spaces.

42. Literals Figurative constants Figurative constants Meaning
ZERO(S) or ZEROES Represents the value 0, one or
more depending on the context
SPACE(S) Represents one or more spaces
HIGH-VALUE(S) Represents the highest value
LOW-VALUE(S) Represents the lowest value
QUOTE(S) Represents single or double
quotes

43. Data names Are named memory locations.
Must be described in the DATA DIVISION before they can be used in the PROCEDURE DIVISION.
Can be of elementary or group type.
Can be subscripted.
Are user defined words.

44. Rules for forming User-defined words
Are used to form section, paragraph and data names.
Can be at most 30 characters in length.
Only alphabets, digits and hyphen are allowed.
Blanks are not allowed.
May not begin or end with a hyphen.
Should not be a COBOL reserved word.

45. Description of data names
All the data names used in the PROCEDURE DIVISION must be described in the DATA DIVISION.
The description of a data name is done with the aid of (1) Level number (2) PICTURE clause (3) VALUE clause

46. Description of data names
Level number
Is used to specify the the data hierarchy.
Level Number Purpose
Record description and independent items
02 to Fields within records and sub items
RENAMES clause
Independent items
Condition names

47. Description of data names
PICTURE clause
Is used to specify the following (1) The data type (2) The storage requirement.
Can be abbreviated as PIC.
Can be abbreviated in case of recurring symbols.
Is used only elementary items.

48. Description of data names
PICTURE clause
Code Meaning
Numeric
A Alphabetic X Alphanumeric V Decimal Point S Sign bit

49. Description of data names
VALUE clause
Is used to assign an initial value to a elementary data item.
The initial value can be numeric literal, non- numeric literal or figurative constant.
Is an optional clause.

50. Group and elementary items
In COBOL the term “group item” is used to describe a data item which has been further subdivided.
A Group item is declared using a level number and a data name. It cannot have a picture clause.
Where a group item is the highest item in a data hierarchy it is referred to as a record and uses the level number 01.

51. Group and elementary items..
The term “elementary item” is used to describe data items which are atomic, that is, not further subdivided.
An elementary item declaration consists of;
a level number,
a data name
picture clause.
An elementary item must have a picture clause.
Every group or elementary item declaration must be followed by a full stop.

52. PICTURE Clauses for Group Items
Picture clauses are NOT specified for ‘group’ data items because the size of a group item is the sum of the sizes of its subordinate, elementary items and its type is always assumed to be PIC X.
The type of a group items is always assumed to be PIC X, because group items may have several different data items and types subordinate to them.
An X picture is the only one which could support such collections.

53. Group Items/Records - Example
WORKING-STORAGE SECTION.
01 STUDENT-DETAILS PIC X(026).
STUDENT-DETAILS
H E N N E S S Y R M L M F

54. Group Items/Records - Example
WORKING-STORAGE SECTION.
01 STUDENT-DETAILS.
02 STUDENT-NAME PIC X(010).
02 STUDENT-ID PIC 9(007).
02 COURSE-CODE PIC X(004).
02 GRANT PIC 9(004).
02 GENDER PIC X(001).
STUDENT-DETAILS
H E N N E S S Y R M L M F
STUDENT-NAME STUDENT-ID COURSE-CODE GRANT GENDER

55. Group Items/Records WORKING-STORAGE SECTION. 01 STUDENT-DETAILS.
02 STUDENT-NAME.
03 SURNAME PIC X(008).
03 INITIALS PIC X(002).
02 STUDENT-ID PIC 9(007).
02 COURSE-CODE PIC X(004).
02 GRANT PIC 9(004).
02 GENDER PIC X(001).
STUDENT-DETAILS
H E N N E S S Y R M L M F
STUDENT-NAME STUDENT-ID COURSE-CODE GRANT GENDER
SURNAME INITIALS

56. LEVEL Numbers & DATA hierarchy
In COBOL, level numbers are used to decompose a structure into it’s constituent parts.
In this hierarchical structure the higher the level number, the lower the item is in the hierarchy. At the lowest level the data is completely atomic.
The level numbers 01 through 49 are general level numbers, but there are also special level numbers such as 66, 77 and 88.
In a hierarchical data description what is important is the relationship of the level numbers to one another, not the actual level numbers used.
01 STUDENT-DETAILS.
02 STUDENT-NAME.
03 SURNAME PIC X(008).
03 INITIALS PIC X(002).
02 STUDENT-ID PIC 9(007).
02 COURSE-CODE PIC X(004).
02 GRANT PIC 9(004).
02 GENDER PIC X(001).
01 STUDENT-DETAILS.
05 STUDENT-NAME.
10 SURNAME PIC X(008).
10 INITIALS PIC X(002).
05 STUDENT-ID PIC 9(007).
05 COURSE-CODE PIC X(004).
05 GRANT PIC 9(004).
05 GENDER PIC X(001).

57. Description of data names
Example
DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-REGNO PIC X(5).
01 WS-NAME.
05 WS-FIRST-NAME PIC A(15).
05 WS-MID-NAME PIC A(15).
05 WS-LAST-NAME PIC A(10) WS-AGE PIC 99V99.
01 WS-SCHOLARSHIP PIC 9(4) VALUE

58. Break

59. Edited picture symbols
Edit symbol Meaning
Z Zero suppression
* Check protection
, Comma insertion
Minus sign insertion
Plus or minus sign insertion

60. Edited picture symbols
Edit symbol Meaning
$ Dollar sign insertion
CR Credit symbol
DB Debit symbol
B Blank insertion
/ Slash insertion
Decimal point insertion
BLANK WHEN ZERO Blank insertion when
the value is zero.

61. Edited picture symbols
Examples
Edit symbol Value Edited value ZZ
*** ***12
$ $0123

62. Edited picture symbols
Examples
Edit symbol Value Edited value
999CR CR
999CR bb
99, ,234
99B

63. PROCEDURE DIVISION Verbs
Data movement verb.
Arithmetic Verbs.
Input / Output Verbs.
Sequence control verbs.
File handling verbs.

64. Instruction Format Specification
Uppercase words are COBOL reserved words.
Underlined words are mandatory.
One of the elements in the flower brackets is mandatory.
Elements in square brackets are optional.
Punctuation symbols are mandatory.
Ellipses indicate addition entries of same type can follow.

65. Input / Output Verbs
ACCEPT Verb Syntax ACCEPT identifier [ FROM { DATE, DAY, TIME, mnemonic-name }]. Examples (1) ACCEPT NUMBER-1. (2) ACCEPT TODAY-DATE FROM DATE.

66. Input / Output Verbs
DISPLAY Verb Syntax DISPLAY { identifier-1, literal-1 } , Examples (1) DISPLAY “The sum is ” SUM.

67. Arithmetic Verbs
ADD
SUBTRACT
MULTIPLY
DIVIDE
COMPUTE

68. ADD Verb
Syntax-1 ADD { identifier-1, literal-1 } [ , identifier-2, literal-2 ] TO identifier-3 [ , identifier-4 ] . . .
Syntax-2 ADD { identifier-1, literal-1 } { identifier-2, literal-2 } [ identifier-3, literal-3 ] GIVING identifier

69. ADD Verb
Examples (1) ADD NUM-1 TO NUM-2. (2) ADD NUM-1, NUM-2 TO NUM-3. (3) ADD 12, NUM-1, NUM-2 TO NUM-3, NUM-4. (4) ADD NUM-1, NUM-2 GIVING NUM-3. (5) ADD 12, NUM-1 GIVING NUM-2, NUM-3.

70. ADD Examples
ADD Cash TO Total.
Before
After
ADD Cash, 20 TO Total, Wage.
Before
ADD Cash, Total GIVING Result.
Before
ADD Males TO Females GIVING TotalStudents.
Before

71. SUBTRACT Verb
Syntax SUBTRACT { identifier-1, literal-1 } [ identifier-2,
literal-2 ] FROM identifier-3 [ , identifier-4 ]
[ , GIVING identifier-5 [ , identifier-6 ] ]

72. SUBTRACT Verb
Examples (1) SUBTRACT NUM-1 FROM NUM-2. (2) SUBTRACT NUM-1, NUM-2 FROM NUM-3. (3) SUBTRACT 5, NUM-1 FROM NUM-2, NUM-3. (4) SUBTRACT 12 FROM NUM-1 GIVING NUM-2. (5) SUBTRACT NUM-1 FROM NUM-2 GIVING NUM-3.

73. SUBTRACT Examples
SUBTRACT Tax FROM GrossPay, Total.
Before
After
SUBTRACT Tax, 80 FROM Total.
Before
SUBTRACT Tax FROM GrossPay GIVING NetPay.
Before

74. MULTIPLY Verb
Syntax MULTIPLY { identifier-1, literal-1 } BY identifier [ identifier-3 ] [ , GIVING identifier [ , identifier-5 ] ]

75. MULTIPLY Verb
Examples (1) MULTIPLY NUM-1 BY NUM-2. (2) MULTIPLY NUM-1 BY NUM-2 GIVING NUM-3. (3) MULTIPLY 5 BY NUM-1 GIVING NUM-2. (4) MULTIPLY NUM-1 BY NUM-2 GIVING NUM-4, NUM-5.

76. DIVIDE Verb
Syntax-1 DIVIDE { identifier-1, literal-1 } INTO identifier [ , identifier-2 ] [ GIVING identifier [ , identifier-5 ] ] ..
Syntax-2 DIVIDE { identifier-1, literal-1 } BY { identifier-2, literal-2 } GIVING identifier-3 [ , identifier-4 ].

77. DIVIDE Verb
Syntax-3 DIVIDE { identifier-1, literal-1 } { INTO , BY } { identifier-2, literal-2 } GIVING identifier-3 REMAINDER identifier-4 .

78. DIVIDE Verb
Examples (1) DIVIDE 5 INTO NUM-1. (2) DIVIDE 6 INTO NUM-1 GIVING NUM-2, NUM-3. (3) DIVIDE NUM-1 BY 3 GIVING NUM-2, NUM-3. (4) DIVIDE NUM-1 BY NUM-2 GIVING NUM (5) DIVIDE NUM-1 BY NUM-2 GIVING NUM REMAINDER NUM-4.

79. MULTIPLY and DIVIDE
MULTIPLY Subs BY Members GIVING TotalSubs
ON SIZE ERROR DISPLAY "TotalSubs too small"
END-MULTIPLY.
Subs Members TotalSubs
Before
After
MULTIPLY 10 BY Magnitude, Size.
Before
DIVIDE Total BY Members GIVING Average ROUNDED.
Before

80. ROUNDED Option
Syntax
Arithmetic statement [ ROUNDED ].
Examples (1) ADD NUM-1, NUM-2, NUM-3 GIVING NUM-4
ROUNDED.
(2) DIVIDE NUM-1 BY NUM-2 GIVING NUM-3 ROUNDED.

81. The ROUNDED option
Receiving Field Actual Result Truncated Result Rounded Result
PIC 9(3)V
PIC 9(3)
The ROUNDED option takes effect when, after decimal point alignment, the result calculated must be truncated on the right hand side.
The option adds 1 to the receiving item when the leftmost truncated digit has an absolute value of 5 or greater.

82. ON SIZE ERROR Option
Syntax Arithmetic statement [ON SIZE ERROR imperative statement . . .]
Examples (1) ADD NUM-1, NUM-2, NUM-3 TO NUM-4 ON SIZE ERROR PERFORM 900-EXIT-PARA.
(2). DIVIDE NUM-1 BY NUM-2 ON SIZE ERROR PERFORM 800-ERROR-PARA.

83. On size error option Yes No
Receiving Field Actual Result SIZE ERROR
PIC 9(3)V
PIC 9(3)V
PIC 9(3). 124
PIC 9(3)
PIC 9(3)V9 Not Rounded
PIC 9(3)V9 Rounded
PIC 9(3)V9 Rounded
Yes No
A size error condition exists when, after decimal point alignment, the result is truncated on either the left or the right hand side.
If an arithmetic statement has a rounded phrase then a size error only occurs if there is truncation on the left hand side (most significant digits).

84. COMPUTE Verb
Syntax COMPUTE identifier [ ROUNDED ] = algebraic expression [ ON SIZE ERROR ] imperative statement.
Example COMPUTE VOLUME = ( 4 / 3) * ( 22 / 7 ) * R ** 3.
Note: If the ROUNDED and ON SIZE ERROR both appear, then the ROUNDED option should precede the ON SIZE ERROR.

85. The COMPUTE Precedence Rules. 179.59 156.25 87 1. ** = POWER NN
2. * = MULTIPLY x / = DIVIDE ÷
3. + = ADD + - = SUBTRACT -
Compute IrishPrice = SterlingPrice / Rate * 100.
Before
After

86. Review Features of COBOL. General Coding and Format rules.
Language Fundamentals.
Input and Output verbs.
Arithmetic verbs.

87. identification division
Review questions
If an entry must begin in area A ,it must begin in
If an entry must begin in area B,it must begin in position
Program-id is the paragraph name that appears in the
The word rounded (precedes, follows) the ON SIZE ERROR clause in an arithmetic statement
Column number 8,9,10,11
12 to 72 any where;
identification division
precedes

88. Review questions 18 digits A numeric literal in COBOL can have at most
A Non numeric literal can have maximum
Indicate True or False
A 01 level entry cannot have a picture class
In COBOL a data name must contain at least 8 characters
A COBOL sentence consists of one or more than one statement the last of which is terminated by a period
160 characters including spaces
False
False
True

89. Any Questions ????

90. Thank you Jyothi Sridhar Kini E&R, Infosys
Mail-id:
Phone: