Cobol Session1

8/6/2019 Cobol Session1

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Abbreviation ofCOmmon Business Oriented Language

One of the oldest computer languages in use (Was developed in late 1950s)

Mainly Used for Information processing in BusinessApplications

Used for generating reports through Batch Processing

Batch processing is also known as periodical processing

Batch Processing Examples: Generation of Utility Bills, Payroll Processing etc.

Also used in Online applications under CICS environment.

Online Processing Examples: Railway/Airline Reservation System, Online

Banking etc.

What is COBOL?


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High Level Language

English-like constructs

Self-documenting Language

File handling capability

Easy to write

Available across several platforms

Largely Machine independent

Advantages ofCobol


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COBOL was Developed In 1959 By AGroup Called CODASYL (COnference on

DAta SYstems Language).

LaterANSI standards were introduced

COBOL 68

COBOL 74

COBOL 85

COBOL 2003 ( Enterprise COBOL )

History ofCobol


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Future ofCobol

COBOL will remain an important language in future also Billions of lines of COBOL source are currently in use with millions added each

year

1000s of COBOL programmers retire every year

There is a continuous requirement of TRAINED man power in COBOL for

Maintenance and Development of COBOL based applications.


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Features Of COBOL

Oriented towardsbusiness applications

English-like

Self-Documenting

Machine independent

Easy to Learn / Read / Write / Test

I/O operations easily designated

Structured Programming Support


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COBOL 74 STD.

OS/VS COBOL VS COBOL II COBOL/370 COBOL FOR MVS & VM

COBOL 85 STD.

DBCS,IMPROVED

CICS

INTERFACE,

31 BIT

ADDRESSING ,

SAA SUPPORT,

ETC.

COBOL 74 STD.

COBOL 85 STD.

DBCS,IMPROVED

CICS

INTERFACE,

31 BIT

ADDRESSING,

SAA SUPPORT,

ETC.

COBOL 74 STD. COBOL 74 STD.

COBOL 85 STD.

DBCS,IMPROVED

CICS

INTERFACE,

31 BIT

ADDRESSING,

SAA SUPPORT,

ETC.

INTRINSICFUNCTIONS,

SUPPORT FOR

LANGUAGE

ENVIRONMENT

INTRINSICFUNCTIONS,

SUPPORT FOR

LANGUAGE

ENVIRONMENT

EXTENSIONS

FOR OOCOBOL,

C INTEROP.

IBM's latest host COBOL compiler

COMPARISON OF IBM COBOL

COMPILERS


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Application Development Cycle

- For writing a COBOL program you have to be provided with program

specification by your BUSINESSANALYST

- ANALYST studies a customers requirement for an application package and

prepares an over all design and finally comes out with a detailed specification for

every program to be developed under an application

- The specification will contain the details of INPUT/OUTPUT file descriptions,OUTPUT report layouts and descriptions, Processing logic and rules, Calculation

methods, etc.

- A Programmer/ Developer writes the code for each module. And tests each

module after development.

- A Testerprepares a plan for testing and also prepares a set of Test data to test

and ensure that the programs work as intended by the designer and customer


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BusinessAnalyst

System Analyst

Programmer Tester

End User


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ACOBOL PRO

GRA

M IS DIVIDED IN

TO

Divisions

Sections

Paragraphs

Sentences

Statements

Words

Characters

Components of a COBOL program


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| | | | |

| | | | |

| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 || 71 | 72 |

|---------- ------| |------ ---|------------------------------ ------------------|1

2

3 4

Columns

1. Sequence NumberArea

2. Indicator Area

3. Area A or Margin A

4. Area B or Margin B

COBOL Coding Format

IndicatorArea Characters

a. * (Asterisk) Comment

b. / (Slash) - Comment + page feed

c. - (Hyphen) - String Continuation


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Sequence NumberArea:

Columns 1 6 - Line numbers. Each line of code may have a 6 digit

line number. Line numbers to be in ascending order

IndicatorArea

* in column 7 Line treated as a comment ; Shown in the source listing

/ in column 7 Line treated as a comment ; Source listing begins a

new page before printing the line

- ( hyphen ) in column 7 Line treated as continuation ofprevious line

Except when non-numeric literals are continued, all trailing spaces on

the preceding line and all leading spaces on the continuation line, are

ignored

Source Coding Rules


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Source Coding Rules (contd.)

Area A

AreaA (columns 8 thru 11)

AreaA Reserved for DIVISION, SECTION & PARAGRAPH headers, File

description entry indicators (FD & SD), level numbers 01 and 77.

Comment lines also accepted, provided column 7 contains an * or /.

Area B

Area B (Columns 12 72 )

Reserved for Filenames associated with FD or SD indicators and the

SELECT clause of Input-Output Section.Level nos. 02 to 49 and 66 and 88

Descriptive clauses and/or data descriptions that make up specific

paragraph entries. Continuation lines, provided column 7 contains a -

(hyphen).

it


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FOUR DIVISIONS OFCOBOL

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DIVISION

S/SECTION

S identify various parts of a COBOL program.

File declarations, descriptions, temporary variables, processing logic,

communication with otherprograms etc., are handled by various DIVISONS/

SECTIONS of a COBOL program.

There are four DIVISIONS in all.

IDENTIFICATION DIVISION. ( MANDATORY )

ENVIRONMENT DIVISION. ( OPTIONAL )

DATA DIVISION. ( OPTIONAL )

PROCEDURE DIVISION. ( MANDATORY )


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FUNCTIONS OF THE FOUR DIVISIONS.

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The IDENTIFICATION DIVISION is used to specify the name of program

and programmer.

The ENVIRONMENT DIVISION is used to define the data sets that are used

by a program and links the data sets to the corresponding DD names of JCL

The DATADIVISION is used to provide the complete descriptions of data

sets including record description and field description and working storage

variables.

The PROCEDURE DIVISION contains executable instructions ( statements

containing VERBS ) to process the data contained in DATADIVISION.

COBOL provides a means for specifying sequence, selection and iteration

constructs to code yourprocessing logic.


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COBOL coding lines start in MarginA or Margin B

DIVISION, SECTION, PARAGRAPH names start in Margin A

FD entries,01,77 level entries, Procedure division paragraph names start in

Margin A

STATEMENTS, 02-49, 66, 88 level entries start in Margin B

Procedure division sentences, statements start in Margin B

COBOL coding rules


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1 2 3 4 5 6 7

123456789012345678901234567890123456789012345678901234567890123456789012

IDENTIFICATION DIVISION.

PROGRAM-ID. SAMPLE1.

AUTHOR. SRG.

DATA DIVISION.

WORKING-STORAGE SECTION.

77 NUM1 PIC 9 VALUE ZEROS.

77 NUM2 PIC 9 VALUE ZEROS.

77 RESULT PIC 99 VALUE ZEROS.

77 WS-NAME PIC X(10) VALUE ARICH INFOTECHS.

PROCEDURE DIVISION.

CALC-RTN1.

ACCEPT NUM1.

ACCEPT NUM2.

MULTIPLY NUM1 BY NUM2GIVING RESULT.

DISPLA

Y "RESULT IS = ", RESULT.STOP RUN.

Sample COBOL program


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What is COBOL and where it is used?

What are the advantages of COBOL?

Who is a Business Analyst?

How is a COBOL Program classified into?

How many divisions are available in COBOL? Name them.

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Recap!!!!!!


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Identification Division

- THE SMALLEST- USED TO IDENTIFY THE PROGRAM AND AUTHOR

- NO SECTIONS

- CONTAINS ONLY PARAGRAPHS

IDENTIFICATION DIVISION

PROGRAM-ID. TEST123.

AUTHOR. TESM.

INSTALLATION. ARICH INFOTECH.

DATE-WRITTEN. 17-01-2010.

DATE-COMPILED. 18-01-2010.

- PROGRAM-ID is the only required Paragraph for this division.

- Program name can be only 8 characters

- All other entries are optional and for documentation purposes only


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N I N N I I I N

his follows the identification division.

his is the most hardware dependent division. he computer and other device requirements are described in this

section.

It has two sections.

N I N N I I I N.

C NFIGU ATI N CTI N.U C -C PUTER. 390. (where the program is compiled)

OBJECT-COMPUTER. DECALPHA. (where the program is executed)

INPUT-OUTPUT SECTION.

FILE-CONTROL.

SELECT employee-master ASSIGN TO DD1

organization is sequential.

I-O-CONTROL.

SPECIAL-NAMES.

CURRENCY SIGN IS literal-1.

DECIMAL POINT IS COMMA.


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DATA DIVISION

- Has TWO sections FILE SECTION and WORKING-STORAGE SECTION

File Section.

- Describes the characteristics of FILES used in the program RECORD SIZE,

BLOCK SIZE, FORMAT ETC

- IT CONTIANS RECORD STRUCTURE AND FIELD DESCRIPTION entries.

Working-Storage Section.

- Declare temporary memory variables used in the program.

- In essence, the contents of FILE SECTION

variables are stored in thedevices like hard disk/printer where as the contents of WORKING-STORAGE

section are in RAM buffers and are lost once the program is terminated


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DATA DIVISION

DA

TA

DIVISIONHA

SF

ou

r SEC

TIONS

FILE SECTION.


LINKAGE SECTION.

LOCAL-STORAGE SECTION.

REPORT SECTION

SCREEN SECTION.

The last 2 sections are not supported in IBM MAINFRAME COBOL

SCREEN SECTION REQUIREMENTSARE TAKEN CARE BY THE OLTP

SOFTWARE CICS


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DATADIVISION

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The DATADIVISION has the following structure

DATA DIVISION.

FILE SECTION.

.. FILE SECTION ENTRIES ..


TEMPORARY MEMEORY VARIABLES,GROUPAND

ELEMENTARY ITEMS..

EXAMPLE:


PROGRAM-ID. SAMPLE1.

AUTHOR. SRG.

DATA DIVISION.WORKING-STORAGE SECTION.

01 Num1 PIC 9 VALUE ZEROS.

01 Num2 PIC 9 VALUE ZEROS.

01 Result PIC 99 VALUE ZEROS.


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Let us start with working-storage section

VARIABLES can be declared in WS section.

Variables are also known as data items or identifiers.

A data item starts with a level number followed by its name, PIC clause andoptionally VALUE and other clauses

A variable name can be maximum of30 chars consisting ofA-Z, 0-9, and

hyphen

No other special characters, no blanks are allowed.

Must have at least one Alphabet

VARIABLES


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DATA ITEMS / VARIABLES

DA

TA

ITEMS CAN

BE ELEMEN

TA

RY ORG

ROUP ITEMS

ELEMENTARY ITEM IS ONE THAT IS NOT FURTHER SUBDIVIDED

A SET OF RELATED ELEMENTARY ITEMS IS CALLED AGROUP ITEM

01 LEVEL IS USED FOR DECLARINGGROUP ITEMS

ELEMENTARY ITEMS WHICHARE NOT PART OF ANY GROUP IS

CALLED INDEPENDENT ELEMENTARY ITEMS

Generally Independent elementary items are declared in WS

with level number 77

Independent elementary items can also be declared with level number

01 from COBOL-85 version


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DATA ITEMS / VARIABLES (Contd.)

01 AND 77 LEVEL ITEM NAMES MUST BE UNIQUE

01 LEVEL IS ALSO USED FOR DECLARINGGROUP ITEMS ,

IN WHICH CASE IT MAY HAVE SUB LEVEL ITEMS WITH LEVELNUMBERS

02-49

02-49 LEVEL DATA ITEMS MAY have duplicates

01 77 levels are used in MARGIN-A where as other levels in MARGIN-B


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Example Code

01 REC1.

05 ID-FIELD1 PIC XX.

05 AMOUNT PIC 9(5)V99.

05 DESCRIPTION PIC X(40).

01 PRINT-REC1.

05 ID-FIELD PIC XX VALUE SPACES.

05 AMOUNT PIC ZZ,ZZ9.99.

05 DESCRIPTION PIC X(40) VALUE SPACES.

PROCEDURE DIVISION.

..

SET-PRINT.

MOVE CORRESPONDING REC1 TO PRINT-REC1.


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COBOL Data Types

There are THREE basic data types in COBOL

Numeric, Alphabetic, Alphanumeric

The contents in ALPHANUMERIC items are left justified

The contents in NUMERIC items are right justified

Poor in type Checking


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Declare Variables in WS

Variables are declared with a level number, user defined name and PIC clauseWORKING-STORAGE SECTION.

77 WS-NAME PIC X(15) VALUE ARICH INFOTECH.

77 WS-CTR1 PIC 9(6) VALUE 1234. 001234

77 WS-CTR2

PIC 9(4) V

ALUE ZERO.

77 WS-LINE PIC X(10) VALUE ALL -. ------------

77 WS-ADDR PIC X(10) VALUE SPACES.

77 WS-AMT PIC 9(4)v9(3) value 12.56. 0012560

Level number 77 indicates the item is independent data item

PIC means PICTURE Clause indicating the type and size of the item

Type can be X A 9 indicating alphanumeric, alphabetic, Numeric items


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Declare Variables in WS (contd.)

VALUE indicates the initial contents of the variable

The constants are three types in COBOL

STRING CONSTANT, NUMERIC CONSTANT, FIGURATIVE CONSTANT

Though the initial values are called constants, the contents canbe modified latein the program.

The max size of X and A is 32000 chars without value clause and 180 with VALUE

clause.

The maximum for numeric data itemmax allowed is 18 digits but mainframe

COBOL allows up to 31 digits. You have to set the compiler option

PARM.COBOL=ARITH(EXTEND)


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More examples

77 WS-CTR2 PIC 9(5) VALUE 123. ( STOREDAS 00123 )77 EMP-NAME PIC A(15) VALUE ARICH INFOTECH .

01 EMP-ADDRESS PIC X(12) VALUE 45, I STREET.

01 WS-GRP.

02 WS-EC PIC 9(3).

02 WS-EN PIC X(12).

02

WS-DOB.03 WS-DD PIC 9(2).

03 WS-MM PIC 9(2).

03 WS-YY PIC 9(2).

01 WS-GRP.

05 WS-EC PIC 9(3).

05 WS-EN PIC X(12).

05 WS-DOB.

10 WS-DD PIC 9(2).

10 WS-MM PIC 9(2).

10 WS-YY PIC 9(2).


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Figurative Constants

COBOL provides special types of constants called Figurative Constants.

They are:

SPACE or SPACES

ZERO or ZEROS or ZEROES equivalent to 0

HIGH-VALUE or HIGH-VALUES equal to Max Value

This consists of All bits on condition in a variable. Represents a non-

standard, non-printable character used to specify the highest value in the

computers collating sequence.

LOW-VALUE or LOW-VALUES equal to Min Value


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EXAMPLE PROCEDURE DIVISION STATEMENT


PROGRAM-ID. PRG1.

DATA DIVISION.


77 WS-NAME PIC X(10) VALUE ARICH INFOTECH.

PROCEDURE DIVISION.

DISPLAY HELLO WS-NAME.

STOP RUN.

Note: DISPLAY statement IN MAIN FRAME COBOL CANNOT

control the LINE or COLUMN position of the SCREEN


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You have to use multiple display statements to show the contents onseparate lines

000100 IDENTIFICATION DIVISION.

200 PROGRAM-ID. PRG1.

300 DATADIVISION.

400 WORKING-STORAGE SECTION.500 77 WS-NAME PIC X(10) VALUE ARICH INFOTECH.

600 PROCEDURE DIVISION.

700 DISPLAY HELLO

800 DISPLAY WS-NAME.

900 DISPLAY HOW ARE YOU?.

1000 STOP RUN.


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Procedu

re to compile and

execu

te aC

OBOL program

1. Allocate two PDS

2. Enter your COBOL program as a member of PDS

3

. Create a JCL nam

ed COMPLIN

K as follows, inA

RICH03

.COBOL.PDSand submit

//ARICH56R JOB NOTIFY=ARICH03,CLASS=M

// JCLLIB ORDER=(ZOS.PROCLIB)

//S1 EXEC PROC=IGYWCL,MEM=PRG1

//COBOL.SYSIN DD DSN=ARICH03.COBOL.PDS(&MEM),DISP=SHR

//LKED.SYSLMOD DD DSN=ARICH03.LOAD.PDS(&MEM),DISP=SHR

//


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HOW TO EXECUTE YOUR LOAD MODULE?

CREATE A JCL NAMED RUNJCL AS FOLLOWS IN ARICH03.COBOL.PDS

AND SUBMIT

//ARICH03R JOB NOTIFY=&SYSUID,CLASS=M

//JOBLIB DD DSN=ARICH03.LOAD.PDS,DISP=SHR

//S1 EXEC PGM=PRG1

//SYSPRINT DD SYSOUT=*//SYSIN DD *

..

/*

//

==================================================================

NOTE: //GO.SYSIN DD * is to be used for giving the input when we use IGYWCLG

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PROGRAM-ID. PRG1.

DATA DIVISION.


77 WS-NAME PIC X(10).

77 WS-NUM PIC 9(5).

PROCEDURE DIVISION.

ACCEPT WS-NAME.

DISPLAY WS-NAME.

ACCEPT WS-NUM.DISPLAY WS-NUM.

STOP RUN.

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ACCEPT


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EXAMPLE: 1


PROGRAM-ID. EX1.

DATADIVISION.


77NA

ME PIC X(15).01 AGE PIC 9(2).

PROCEDURE DIVISION.

PARA-1.

ACCEPT NAME.

ACCEPT AGE.

DISPLAY HELLO " NAME.

DISPLAY YOUR AGE IS " AGE.

STOP RUN.


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ACCEPT can be used to capture system registers like DATE, TIME etc.


PROGRAM-ID. PRG1.

DATADIVISION.


77 WS-DATE PIC 9(8).PROCEDURE DIVISION.

ACCEPT WS-DATE

FROM DATE YYYYMMDD.

DISPLAY WS-DATE.

STOP RUN.


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IDENTIFICATION DIVISION.PROGRAM-ID. PRG1.

DATA DIVISION.


77 WS-TIME PIC 9(8) VALUE 0.

PROCEDURE DIVISION.

ACCEPT WS-TIME FROM TIME.DISPLAY WS-TIME.

STOP RUN.


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RECAP!!!!!

What is the purpose of using theEnvironment Division?

What are the different section available inData Division.

What is the purpose of a Display statement?

When do you use an ACCEPT keyword?

List out atleast five different Reserved wordsthat you have come across so far.

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Cobol Session1

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