Eds Cobol Training

8/7/2019 Eds Cobol Training

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03-23-05

30 Sept 2005

page 1 EDS Internal

COMMON BUSINESS ORIENDTED LANGUAGECOMMON BUSINESS ORIENDTED LANGUAGE

E D S India A D U.


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Presentation Title Here, Place on Slide Master, Trebuchet Font, 9 Pt., Normal 30 Sept 2005 page 2 EDS Internal

OBJECTIVESOBJECTIVES

Understand the standard format of the COBOL program.

Write COBOL programs using modular design techniques

Compile, Link edit and Execute the soure code.


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INTRODUCTIONINTRODUCTIONBE

COBOL stands for COMMON BUSINESS ORIENTED LANGUAGE.

COBOL can be referred as

High-level programming language oriented towards businessapplications

Procedural language

Problem oriented and Machine independent


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HISTORYHISTORY

Developed in 1959 as standard language to meet businessneed.

Committee was formed to maintain the COBOL.

Included representatives from academia, business,computer manufacturers.`


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STANDARD VERSIONS OF COBOLSTANDARD VERSIONS OF COBOL

1960s Versions of COBOL compilers

1968 First COBOL standard set by American nationalStandards Institute (ANSI) known as COBOL-68

1974 Second COBOL known as COBOL-74 was approvedby ANSI.

1985 ANSI approved the COBOL-85 in which structured

programming techniques were incorporated.


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CHARACTERSTICSCHARACTERSTICS

COBOL self documenting.

COBOL is simple

COBOL is non proprietary (Portable)

COBOL is maintainable


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LANGUAGE CONSTRUCTIONLANGUAGE CONSTRUCTION

COBOL is like English language

Character is the lowest component

Word is made up of one or more characters.

Clause consists of word and characters.

Statement is syntactically valid combination of words andclauses.


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Statement is syntactically valid combination of words andclauses.

Sentence is a sequence of one or more statements

terminated by period.

Paragraph consists of one or more statements

Section consists of one or more paragraphs.


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Division consists of one or more paragraphs.

Program is made up of divisions.


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CHARACTER SETCHARACTER SET

Set of 51 characters

0,. 9

A,.Z

b

+, -, *, /, (,), =, $, ., ,

DIGITS

LETTERS

SPACE/BALNK CHARACTER

SPECIAL SYMBOLS


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WORDSWORDS

User defined words

Words declared by programmer like paragraphnames, identifiers etc.

Reserved words

Words that are having specific meaning to thecompiler


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CODING FORMATCODING FORMAT

Columns

1 6 Sequence numbers identifying pages or lines of aprogram

7 Continuation, comment or starting of a new page

872 Program statements

73-80 Remarks.

in column 7

* designates the entire line is as a comment

/ forces page break when printing source listing

- to indicate a continuation of non numeric literalcolumns 8 72 divided into two areas.


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CODING FORMATCODING FORMAT

AREA A - Columns 8 to 11

AREA B - Columns 12 to 72

Division, Section and Paragraph names must all begin inArea A and end with a period.


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DIVISIONSDIVISIONS

COBOL program contains up to 4 separate divisions in thefollowing order

IDENTIFICATION DIVISION

ENVIRONMENT DIVISION DATA DIVISION

PROCEDURE DIVISION


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IDENTIFICATION DIVISIONIDENTIFICATION DIVISION

First division of a COBOL program

Identifies the program name to the Operating system

Provides documentation about program

Should begin in Area A.


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Syntax

IDENTIFICATION DIVISION.PROGRAM-ID. PROGRAM NAME.

AUTHOR.COMMENT ENTRY

.INSTALLATION.COMMENT ENTRY.DATE-WRITTEN.COMMENT ENTRY.DATE-COMPILED.COMMENT ENTRY.SECURITY.COMMENT ENTRY.


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Paragraph PROGRAM-ID followed by user defined name ismandatory. Other paragraphs are optional

Security here does not pertian to the operating systemsecurity, but the information that is passed to the user ofthe program about the Security features of the program.


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ENVIRONMENT DIVISIONENVIRONMENT DIVISION

Machine dependent division

The division is optional but for file handling it is essential

Should begin in Area A.

Division is terminated by a period.

Describes the computers used, devices, peripherals etc.

Contains two sections namely, CONFIGURATION andINPUT-OUTPUT


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CONFIGURATION SECTIONCONFIGURATION SECTION

Describes the computer to be used for compiling andexecuting the program.

Consists of the following paragraphs

SOURCE COMPUTER

OBJECT COMPUTER

SPECIAL NAMES.


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SOURCE COMPUTERSOURCE COMPUTER

Used to specify the name of computer for compiling theCOBOL program.

The With Debugging Mode option can be mentionedenabling the compiler to include D in the 7th column for alllines as syntax.

Syntax

SOURCE COMPUTER. XYZ-2901


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OBJECT COMPUTEROBJECT COMPUTER

Used to specify the name of the computer for executingthe program

Syntax

OBJECT-COMPUTER. Computer-name

MEMORY SIZE integer-1 CHARACTERS/WORDS

PROGRAM COLLATING SEQUENCE IS alphabet-name

SEGMENT-LIMIT IS integer-2.


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OBJECT COMPUTEROBJECT COMPUTER

Memory Size used to indicate the amount of storageavailable to Object computer.

The Program Collating Sequence clause specifies thecollating sequence that is to be used to compare non-numeric data items. The alphabet-name is to be defined inSpecial names paragraph.

The Segment-Limit clause is used to indicate that the

section having segment number less than the specifiedshould be held in Permanent area of storage.


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SPECIAL NAMESSPECIAL NAMES

Is used to relate some IBM specified environment names touser defined names.

Regardless of number of entries in this paragraph thereshould be only one period in the end.

Syntax

SPECIAL-NAMES. CURRENCY SIGN IS literal-1

DECIMAL-POINT IS COMMA

CHANNEL integer IS mnemonic-names

ALPHABET alphabet-name ISSTANDARD/NATIVE/implementer name

Implementer-name IS mnemonic-name.


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CURRENCY SIGN literal-1

used to change the currency sign other than $ with onecharacter symbol (literal-1).

DECIMAL-POINT IS COMMA Used to interchange the roles of . and , as editcharacters.

CHANNEL integer IS mnemonic-name

Used to control the line spacing of line printers.

The mnemonic-name can only be used in a WRITEstatement.


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ALPHABET alphabet-name ISSTANDARD/NATIVE/implementer name

Implementer-name is mnemonic-name

Used to indicate the collating sequence

Standard stands for the ASCII collating sequence

NATIVE stands for the computers own collatingsequence


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INPUTINPUT--OUTPUT SECTIONOUTPUT SECTION

Contains information regarding files to be used in theprogram

Consists FILE-CONTROL and I-O-CONTROL (INPUT-

OUTPUT-CONTROL) paragraphs.


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FILEFILE--CONTROLCONTROL

Associates each file used in program with an external DDname. The DD name is associated to a physical file in JCL.

The simplified format of file association is done using

SELECT clause.

Coding rules

SELECT clause must appear first

Other clauses can appear in any order

Each clause must start in Area B.


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II--OO--CONTROLCONTROL

Optional paragraph.

Must begin in Area A.

Specifies when check points are to be taken

Specifies the storage areas to be shared by different files


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DATA DIVISIONDATA DIVISION

Used to define data needed to be accessed by program

Describes input and output format of data files

Defines any constants and work areas

Consists of three sections namely

FILE SECTION

WORKING STORAGE SECTION

LINKAGE SECTION


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FILE SECTIONFILE SECTION

Includes the description of all the files.

SYNTAX of file description

FD file-name

RECORD IS OMITTED

LABEL

RECORDS ARE STANDARD

RECORD CONTAINS integer-1 CHARACTERS

BLOCK CONTAINS integer-2 RECORDS


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FILE SECTIONFILE SECTION

LABEL RECORDS clause used if labels stored in file

BLOCK CONTAINS clause indicates blocking factor for diskfiles.

RECORD CONTAINS clause indicates size of each record.

Defining a Record

Each FD followed by record description entries for the file.

Record name is defined at 01 level considered highestlevel of data

Fields within a record are defined at subordinate levelwith level numbers from 02 to 49.


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WORKINGWORKING--STORAGE SECTIONSTORAGE SECTION

Must start in Area A and end with Period.

All items must be defined at 01 level or at subordinate to01 level

Rules for user-defined entry names apply

Elementary items :

Must include PICTURE (PIC) clause

May be assigned initial value with VALUE clause


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LITERALS AND FIGURATIVE CONSTANTSLITERALS AND FIGURATIVE CONSTANTS

Literal is a constant representing a number or non-number

(Alpha numeric) like 33.3 or TEACHER

Literals are storable in a memory location having a userdefined name called Data name or identifier or Variable orField

Figurative constant is a COBOL reserved word representingfrequently used constants like ZEROS or SPACES

Figurative constants are used in program for betterreadability.

Ex: MOVE SPACES TO WS-RECORD.

Literals are classified into Numeric and Non-numeric literals


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NUMERIC LITERALNUMERIC LITERAL

Must contain at least one digit.

+ or sign, if used must be the left most character

Not more than one decimal point

Decimal may not be the right most character

Maximum of 18 digits

TOTAL-COUNT PIC 9(3) VALUE 100.


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NONNON--NUMERIC LITERALNUMERIC LITERAL

May consist of any character in the character set

Must be enclosed in quotes

A numeric literal in quotes is non-numeric literal

Maximum length of 120 characters

COMPANY-NAME PIC X(3) VALUE EDS.


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FIGURATIVE CONSTANTSFIGURATIVE CONSTANTS

List of Figurative constants

ZERO/ZEROS/ZEROES

Quote/Quotes

Space/Spaces

HIGH VALUE/HIGH VALUES

LOW VALUE/LOW VALUES

ALL

One or more zeros

One or more

One or more spaces

Value in collating sequence

Value in collating sequence

One or more string vlaues


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DATA DESCRIPTIONDATA DESCRIPTION

The general format of data description is Level Number

Data name

Filler clause


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LEVEL NUMBERSLEVEL NUMBERS

Specifies the hierarchical structure of data item

Is a two digit number starting from 01.

Single digit numbers must be written in a two-digit formwith a 0 or space preceding them.

Are values taken from set of integers between 1 and 40, orone from 66, 77 and 88 which are called Special levelnumbers


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LEVEL NUMBERSLEVEL NUMBERS

01 level Specifies a group of data items called record or anelementary data item

Must begin in Area A

02 49 levels

Specifies group items or elementary item within a record.

Group level data items will not have Picture Clause


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SPECIAL LEVEL NUMBERSSPECIAL LEVEL NUMBERS

66 identifies items that contain RENAME clause

77 identifies independent elementary data item

77 has to appear only as elementary data item

88 identifies any condition name that is associated with aparticular value of conditional variable


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DATA NAMESDATA NAMES

Identifier name or Data name should not exceed 30characters

There should be at least one alphabet anywhere in thename.

Only special character allowed is (Hyphen) but shouldnot be at the beginning or at the End.

Should be unique within a record

If Data name is duplicated across records then it should bequalified as identifier-name of Record name


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DATA NAMESDATA NAMES

Examples CURRENT-DATE

EMPLOYEE

11RAIL

99-DETAIL-LINE

MOVE BALANCE OF BILLING-RECORD TO TOTAL-AMOUNT


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FILLERFILLER

Used whenever there is no specific reference to fields in arecord.

Used wherever there is fixed information like SPACES orHeadings are stored.

Example

01 DETAIL-RECORD

05 FILLER PIC X(05) VALUE SPACES.

05 NAME PIC X(20).05 PIC X(02) VALUE SPACES.

05 FILLER PIC X(05) VALUE BASIC.

05 AMT PIC 9(9)V99.


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PICTURE CLAUSEPICTURE CLAUSE

Describes the class (numeric, alphabetic, alphanumeric),sign(signed/unsigned), decimal point location and size of adata item.

Specified for every elementary data item

Type Character String Remark

Numeric 9 Used for arithmeticoperations

V Assumed decimal point

S Signed data item

P Position of assumeddecimal point when thepoint lies outside dataitem


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PICTURE CLAUSEPICTURE CLAUSE

Type Character String RemarkAlphabetic A Data item contains only a

letter or space

B Blank insertion character

Alpha numeric X Data item contains only

allowable character fromthe COBOL character set

Examples

01 COMPANY PIC X(10). - Defines 10characters of Alphanumeric.

01 BASIC-AMOUNT PIC 9(9)V99. Defines9 digits before decimaland two digits afterdecimal. The decimalwill not be displayed.


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EDITED PICTURE CLAUSEEDITED PICTURE CLAUSE

Edited Picture Clause

Used to display Numeric and other data in the userreadable format

Edited types

Numeric data

Alphabetic

Alphanumeric


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EDITED PICTURE CLAUSEEDITED PICTURE CLAUSE

PIC OF THE FIELD NUMERIC VALUE EDITED VALUE

ZZZV99

* * 999

$ * *999

-ZZZV99

+999

+999

9999+

ZZ,Z99

ZZZZ.ZZ

$$$$9.99

99B99B99

09990

999/999/99

38^4

00052

985

-46^52

-382

382

-382

2456

5

342

46

456

3254

b3840

* * 052

$**985

-b4652

-382

+382

0382-

b2,456

bbbb.05

b$342.00

00b00b46

04560

000/032/54

ZZZ.99 BLANK WHEN ZERO

999.99 BLANK WHEN ZERO

2 5

0

bb2.50

bbbbbb


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VALUE CLAUSEVALUE CLAUSE

Assigns initial value to a data item.

Should not exceed the picture clause

Should be consistent with the picture clause

Not used for for items whose size is variable

Example 01 WS-RECORD

05 WS-COMPANY PIC X(03) VLAUE EDS.

05 FILLER PIC X(15) VALUE ALL -.


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USAGE CLAUSEUSAGE CLAUSE

Specifies how data item is represented internally

Types

DISPLAY number of bytes required is equal to the size ofdata item. This is default type.

COMPUTATIONAL Maintained in Binary and only forintegers. Stored either in half or full word.

Syntax

USAGE IS DISPLAY

COMPUTATIONAL OR COMP , COMP -1, COMP-2, COMP-3


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SIGN CLAUSESIGN CLAUSE

Indicates the data item is Signed.

Only for numeric fields

Picture clause should contain S

Usage should be display

To represent the position either LEDING or TRAILING can beused.


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OCCURS CLAUSEOCCURS CLAUSE

Used to represent and store table of values When used allocates physically contiguous memory

locations to store table values

Values are accessed either by using index or subscript

Example

01 WS-TABLE.

05 WS-NAME OCCURS 10 TIMES PIC X(20).

01 WS-TABLE.

05 WS-RECORD OCCURS 15 TIMES.

10 WS-DEPT PIC X(10).

10 WS-DIV PIC 9(05).


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REDEFINES CLAUSEREDEFINES CLAUSE

Allows to reference same memory area for more than onedata-name with different formats and sizes.

Syntax

Level-number data-name-1 REDEFINES data-name-2

Rules

Level-number of data-name-1 and data-name-2 must beidentical and not 66 or 88

Redefines clause must follow immediately after data-name-2

data-name-1 cannot have value clause

data-name-1 size should not exceed data-name-2 size


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REDEFINES CLAUSEREDEFINES CLAUSE

Rules Multiple Redefinitions are allowed provided no newstorage areas defined in between

At 01 level, OCCURS and REDEFINES cannot becombined


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RENAMES CLAUSERENAMES CLAUSE

Regrouping of elementary data items in a Record.

Example

01 WS-RESPONSE.

05 W-CHAR-123 PIC XXX.05 W-CHAR-4 PIC X.

05 W-CHAR-56 PIC XX.

66 ADD-RESPONSE RENAMES W-CHAR-123.

66 VIEW-RESPONSE RENAMES W-CHAR-123 THRUW-CHAR-4.

66 DELETE-RESPONSE RENAMES W-CHAR-123 THRUW-CHAR-56.


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JUSTIFIED CLAUSEJUSTIFIED CLAUSE

Overrides standard positioning rules for a receiving stemof the alphabetic or alphanumeric categories

Default is Left Justified

Does not alter initial settings as determined by the valueclause

May not be specified at 66 and 88 level.

Example

01 WS-CHAR PIC X(05) JUSTIFIED RIGHT.


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PROCEDURE DIVISIONPROCEDURE DIVISION

Contains statements which specify the operations to beperformed

Last division in a COBOL program

Contains following structure


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DIVISION Is a block of code, usually containing one or moresections

Starts with a Division name and ends where a newDivision starts or program text ends

SECTION

Is a block code usually containing one or moreparagraphs.

Starts with a Section name and ends where next sectionstarts or program text ends


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PARAGRAPH A block of code made up of one or more sentences

Starts with a paragraph name and ends where nextparagraph or next section starts or program text ends

Sentences and Statements

Sentence consists of one or more statements and isterminated by a period

Example

MOVE 0.12 TO TAX-RATECOMPUTE PRICEA = PROD-COST * TAX-RATE


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Statement consists of a COBOL verb and an operand oroperands

Example

SUBTRACT TAX FROM GROSS-PAY GIVING NETPAY.


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Guidelines

Paragraph names section names should start in Area A

Statements and Sentences should start in Area B

Section names and Paragraph names are user defined

Section names must be unique and must be different fromparagraph names

Paragraph names must be unique in a section

If paragraph name is duplicated across sections then it shouldbe qualified as paragraph-name of/in section name


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Statements in Procedure division

Can be broadly classified as

Imperative statements which directs the program to take aspecific action during execution

Examples: MOVE , ADD, GOTO , EXIT

Conditional statements - Specified that the truth of acondition is to be determined and that the subsequent action ofthe object program is dependent on this truth value

Examples: IF, EVALUATE, ADDON SIZE ERROR

Compiler Directive statement is beginning with a compilerverb, that causes compiler to take specific action duringcompilation

Examples: USE, COPY



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Explicit Scope Terminator Terminates the scope of theconditional statements

Examples : END-IF, END-READ, END-EVALUATE,

END-CALL, END-SORT

Implicit Scope Terminator is a period that terminates thescope of all previous statements not yet terminated

DATA MOVEMENTDATA MOVEMENT


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MOVE

To move data into a place in a memory

Format

MOVE {IDENTIFIER-1/LITERAL-1} TO IDENTIFIER-2,[,IDENTIFIER-3],

RULES

Only one sending field, one or more receiving fields

Value of the sending field remains unaltered after the

statement execution



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Numeric Data Transfer Rules When sending field is numeric or numeric-edited, thedata movement is called Numeric data transfer

Dominant factor is the decimal points alignment in two

the fields

If the receiving field is not large enough then truncationoccurs either ends or both the ends

If the receiving field is large then the unused positionswill be filled with spaces.



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Alphanumeric Data Transfer Rules

When both the sending and receiving fields arealphabetic, alphanumeric or alphanumeric edited the datamovement is called Alphanumeric

Receiving field is filled from left to right

When receiving field is smaller then truncation occursfrom the right, compiler will give warning



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Group Moves

When at least one of the fields is a group item, it iscalled Group Move

Example

01 RECORD-1.

05 A1 PIC 9(3).

05 A2 PIC A(2).

05 A3 PIC XXXX.

01 RECORD-2.

05 A1 PIC 9(3).05 A2 PIC A(2).05 A3 PIC XXXX.

MOVE RECORD-1 TO RECORD-2.



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Move Corresponding

When the names of the corresponding data item of twogroups are same, this statement can be used forsubstitute for a set of move statements

Example

01 PAY-REC.

05 EMP-NO PIC 9(05).

05 EMP-NAME PIC X(20).

01 PRINT-REC.

05 FILLER PIC X(05).

05 EMP-NO PIC 9(05).05 FILLER PIC X(05).

05 EMP-NAME PIC X(20).

MOVE CORRESPONDING PAY-REC TO PRINT-REC.

ARITHMETIC VERBSARITHMETIC VERBS


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ADD

To sum two or more numbers and store the result

ADD [CORRESPONDING] [Identifier-1/Literal-1] [Identfier-2/Literal-2] [TO /GIVING] Identifier-3, Identifier-4..

ExampleADD A TO B.

ADD A , B GIVING C.

ADD CORR OLD-REC TO NEW-REC.



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SUBTRACT

Used to subtract one or the sum of two or more fromone or more numbers

SUBTRACT [CORR] [Identifier-1/Literal-1] [Identifier-2/Literal-2] [FROM/GIVING] Identifier-3 Identifier-4.

Example

SUBTRACT A FROM B.

SUBTRACT A B FROM C.



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MULTIPLY

Used to multiply one or more multiplicands by multiplier

MULTIPLY {IDENTIFIER-1 BY IDENTIFIER-2[ ,IDENTIFIER-3]...LITERAL - 1}[GIVING IDENTIFIER-4 [ , IDENTIFIER-5]...]

Example

MULTIPLY A BY B.

MUYLTIPLY A BY B GIVING C.

MULTIPLY 2 BY A.



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DIVIDE

Used to divide one number by another

DIVIDE {Identifier-1 / Literal-1}INTO[BY] identifier-2 { ,identifier-3}....[GIVING identifier-4 [ ,identifier-5]...][REMAINDER identifier-6.

ExampleDIVIDE 5 INTO A.

DIVIDE A INTO B GIVING C.

DIVIDE A BY B GIVING C REMINDERD.



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COMPUTE

Used as a substitute for any other arithmetic verbs likeADD, SUBTRACT, MULTIPLY and DIVIDE.

COMPUTE IDENTIFIER-1 [ROUNDED][ , IDENTIFIER-2 [ ROUNDED ] ]= ARITHMETIC-EXPRESSION[ : ON SIZE ERROR]IMPERATIVE STATEMENT.

ARITHMETIC OPERATORSARITHMETIC OPERATORS


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ARITHMETIC OPERATORSARITHMETIC OPERATORS

Permitted operators

** Exponentiation

/ Division

* Multiplication

- Subtraction

+ Addition

ARITHMETIC OPERATIONARITHMETIC OPERATION


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ARITHMETIC OPERATIONARITHMETIC OPERATION

ROUNDED OPERATION

It will round the number to the picture clause duringarithmetic operations.

Cant be specified for the identifier that receives theremainder in a Divide operation

ADD WS-A WS-B GIVING WS-C ROUNDED

ON SIZE ERROR

If the result after an arithmetic operation exceeds thelargest value that can be accommodated in the result field

the error occurs is called ON SIZE ERROR Used to continue the process instead of terminatingbecause of error.

ADD A TO B ON SIZE ERROR PERFORM ERROR-PARA.

COBOL DEFINED VERBSCOBOL DEFINED VERBS


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ACCEPT

To transfer data from an input/output device, or systeminformation contained in the specified data items likeDATE, TIME etc.

ACCEPT Identifier [FROM mnemonic name

DATE / DAY/ TIME / DAY-OF-WEEK]

DISPLAY

Used to display data on to a terminal

DISPLAY {identifier-1 identifier-2 literal-1} ,literal-2

UPON [mnemonic name]

Example: DISPLAY TOTAL STRENGTH = TOTAL-ST



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INITIALIZE

Used to initialize value of either a group item or anelementary item

INITIALIZE {identifier-1 } . . .REPLACING { ALPHABETIC

ALPHANUMERICNUMERICALPHA-NUMERIC-EDITED.NUMERIC-EDITED }

DATA BY { identifier-2literal-2 }

CONDITIONAL AND UNCONDITIONAL TRANSFERCONDITIONAL AND UNCONDITIONAL TRANSFER


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Simple IF statement

IF condition

statement-1

statement-2

ELSE

statement-3

statement-4

END-IF.



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Nested IF statement

IF condition-1

IF condition-2

statement-1

ELSE

IF condition-3

statement-3

END-IF

END-IF

END-IF.



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EVALUATE Statement

EVALUATE SUBJECT-1 [ALSO SUBJECT-2]...

{WHEN OBJECT-1 [ALSO OBJECT-2}...}

[WHEN OTHER {IMPERATIVE-STATEMENT-2}...]

[END-EVALUATE].

Can be used instead of nested IF statements



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GO TO statement

Is an unconditional transferring of control to thespecified paragraph

Advised to avoid GO TO as the structured programmingtechnique doesnt support unconditional transferstatements

Example : GO TO REPORT-PARA.

ALTER

Used to modify the targets of GO TO statements written

elsewhere in the procedure division.ALTER PROCEDURE-NAME-1 TO

[PROCEED TO ] PROCEDURE-NAME-2[PROCEDURE-NAME-3 TO {PROCEED TO }

PROCEDURE-NAME-4 ]....

PERFORM STATEMENTPERFORM STATEMENT


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A PERFORM statement is used to execute a group of

consecutive statements elsewhere in the program, under aparagraph

Types of PERFORM

PERFORM Para-name-1.

Para-name-1 specifies the range, which containsstatements to be executed

PERFORM para-name-1 thru para-name-2.

This statement executes all the statements

beginning in para-name-1 till the last statement inpara-name-2 including the paragraphs in betweenboth the paragraphs



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Types of PERFORM

PERFORM para-name-1 [THRU para-name-2] {identifier-1/ integer} TIMES

This is a looping statement which executes thespecified range of statements a fixed number of times.

PERFORM para-name-1 [THRU para-name-2] UNTILcondition.

This statement executes the specified range ofstatements repeatedly until the condition becomesTRUE.

The condition is to be made TRUE within theparagraph performed



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Types of PERFORM

PERFORM VARYING {identifier-1 FROM {identifier-2 /integer-1} BY {identifier-3 / integer-2}UNTIL Condition-1 AFTER identifier-1FROM {identifier-2/integer-1}BY {identifier-3/integer-2} UNTIL Condition-2

[imperative statement]END-PERFORM.

Example

PERFORM VARYING I FROM 1 BY 1 UNTIL I > 3AFTER J FROM 1 BY 1 UNTIL J > 4Display SALE ( I , J )

END-PERFORM.



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RELATIONAL CONDITION

Compares two operands either of which can beidentifier literal, arithmetic expression or index-name

A non-numeric literal can be enclosed in parentheseswithin a relational condition

Relational operators are: < , , >=

NOT GREATER THAN / LESS THAN/ EQUAL TO

SIGN CONDITION

Determines whether or not the algebraic value of a

numeric operand is greater than or less than or equal toZero

Possible conditions are

POSITIVE, NEGATIVE OR ZERO

CONDITIONAL EXPRESSIONSCONDITIONAL EXPRESSIONS


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CLASS CONDITION

Determines whether the content of data item isalphabetic, numeric or contains only characters in theset of characters specified by the CLASS clause in theSPECIAL NAMES paragraph

CONDITION-NAME CONDITION Tests a conditional variable to determine its value isequal to any value(s) associated with the conditionname

Are declared at 88 level

NEGATED CONDITION

A condition is negated by using use of operator NOT



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COMPOUND CONDITION Two or more conditions can be logically connectedto form a compound condition

Possible values are: AND, OR

FILE HANDLINGFILE HANDLING


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N NGN NG

RECORD : is a collection of relevant fields pertaining to an

item/case/account/transaction FILE

Is a collection of relevant records of an application

Is organized in storage media either in SEQUENTIALor INDEXED or RELATIVE way.

SEQUENTIAL FILES

Records can be accessed in the order in which theyappear in the file

Records can be appended at the end of the file butcannot be inserted

Records cannot be deleted

FILE HANDLINGFILE HANDLING


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INDEXED FILES

Records can be accessed Randomly or Sequentiallyusing key called Primary-key

There can be more than one key called Alternatekeys to access records

Records can be inserted and deleted

FILE HANDLING STEPSFILE HANDLING STEPS


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STEP 1:

All files handled in a program should be assigned tological name

The DDNAME assigned, Organization of the file, itsprimary key and alternate keys to be specified in File-control paragraph.

STEP-2:

Describe the details like record-name, record structurein File section including number of records grouped asBLOCK for input output operation

STEP-3

Open the files to do read/write operations in Proceduredivision.

FILE HANDLING STEPSFILE HANDLING STEPS


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STEP 4:

If we have to read records then READ statement shouldbe used

Syntax: READ file-name

STEP 5:

If we have to write record then WRITE statement shouldbe used

Syntax: WRITE record-name

STEP 6:

After all operations are completed the file has to beCLOSED to disconnect file from COBOL program

Syntax: CLOSE file-name

SELECT STATEMENTSELECT STATEMENT


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Syntax:

SELECT file-name ASSIGN TO DD NameORGANIZATION IS[SEQUENTIAL/INDEXED/RELATIVE]

ACESS MODE IS[SEQUENTIAL/DYNAMIC/RANDOM]

[RECORD KEY data-name-1 ]

[ALTERNATE KEY IS data-name-2. WITHDUPLICATE]

FILE-STATUS IS data-name-2.



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ORGANIZATION CLAUSE

Following file organizations can be chosen

o SEQUENTIAL

This option is used for PS data set or VSAM ESDS.

The records are places in first come first servedbasis

o INDEXED

This option is used to handle a VSAM KSDS

Key field called Primary key should be defined

o RELATIVE

This option is used to handle a VSAM RRDS

Record number is used to access records



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ACCESS MODE CLAUSE

Based on Organization file can be accessed in differentmodes

o SEQUENTIAL Access mode To access records insequential order

o RANDOM Access mode To access particular recordof an indexed / relative file provided key value is setprior to read / write operation

o DYNAMIC Access mode To access a particular

record or in sequential order from an indexed / relativefile



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RECORD KEY PHRASE

To be defined for indexed files

To be unique and is to be part of indexed record

ALTERNATE KEY PHRASE

To be defined if records are to be read by using keyother than Primary key

Need not be unique but need to be part of the record

FD ENTRYFD ENTRY


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Syntax

FD file-name.

[BLOCK CONTAINS [int-1 TO] int-2RECORDS[CHARACTERS]

[RECORDS CONTAINS{int-3 to} int-4 CHARACTERS

[LABEL RECORD/RECORDS IS/ARE STANDARD/OMITTED

RECORDING MODE [F/V]

[DATA RECORD/RECORDS IS/ARE data-name-2

01 record-name

05 field-1 PIC X(10).

.

FD ENTRYFD ENTRY


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BLOCK CONTAINS / RECORD CONTAINS PHRASE

Length of the record can be specified in terms ofcharacters

Number of characters / records for a Block can bespecified

RECORDING MODE CLAUSE

Specifies as that all the records in a file are of samelength (FIXED) or different (Variable )

FD ENTRYFD ENTRY


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BLOCK CONTAINS / RECORD CONTAINS PHRASE

Length of the record can be specified in terms ofcharacters

Number of characters / records for a Block canbe specified

RECORDING MODE CLAUSE

Specifies as that all the records in a file are ofsame length (FIXED) or different (Variable )

INPUT AND OUTPUT STATEMENTSINPUT AND OUTPUT STATEMENTS


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OPEN Statement

OPEN INPUT file-name - Connects data set to programto records from the first enabling to read records

OPEN OUTPUT file-name Connects data set toprogram though file is empty enabling to write records

OPEN I-O file-name Connects data set to program to

Read/ Write / Rewrite the records to file OPEN EXTEND file-name Connects the existing data setto program to append new records at the end of theexisting records in the file

WRITE

Adds records to the file

Key to be used for indexed file



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START

Establishes the current location in the cluster for aREAD NEXT statement

This doesnt retrieve record

It only sorts the current record pointer described underFile position indicator

READ

Used to read record from the file

Reads next record for sequential file

Reads the corresponding key specified



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REWRITE

Updates record

DELETE

Logically removes the records from the

Indexed/relative files

CLOSE

Disconnects file from the program

SUBPROGRAMSSUBPROGRAMS


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Programs compiled and stored in library to be called

when needed

The program that calls another program is referred ascalling program, and the program it calls is referred ascalled program

Called program itself can call another program

During execution, called program can either transfer

control back to the calling program or end the run unit



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ADVANTAGES

Avoids duplication effort

Improves programmer productivity

Provides greater flexibility

Changes to the called program can be made withoutchanging the calling program

Results in greater standardization



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LINKAGE SECTION

Describes data made available for anotherprogram

Storage for data items within the program is notreserved because the area exists elsewhere

Value clause may not be specified for items otherthan 88 level items

STATIC CALL

The compiler treats the CALL literal statementwhere the literal is program name, as a static call

when NODYNUM compiler option is in effect

DYNAMIC CALL

Loads the subprogram at the run time



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CALL by Reference or by Content To pass an identifiers value only then use CALLBY REFERENCE

To pass literals value then use CALL BY CONTENT

STRING, UNSTRING AND INSPECT STATEMENTSSTRING, UNSTRING AND INSPECT STATEMENTS


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STRING Statement Strings together the partial or complete contents oftwo or more DATA ITESM or LITERALS into single dataitem

STRING IDEN

TIFIE

R1DELIMI

TED BYIDENTIFIER2

LITERAL1 LITERALSSIZEINTO IDENTIFIER3 WITH POINTERIDENTIFIER4ON OVERFLOW IMPERATIVE STATEMENT1NOTON OVERFLOW IMPERATIVESTATEMENT2

END-STRING



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UNSTRING Statement Causes contiguous data in a sending field to beseparated and placed into multiple receiving fields

UNSTRING IDENTIFIER1 DELIMITED BYALL IDENTIFIER2 LITERAL1

ORALL IDENTIFIER-3 LITERAL2INTO IDENTIFIER4 DELIMITERIN

IDENTIFIER5COUNT INIDENTIFIER6

WITH POINTER IDENTIFIER7TALLYING IN IDENTIFIER8

ON OVERFLOW IMPERATIVESTATEMENT1

NOTON OVERFLOW IMPERATIVESTATEMENT2

END-UNSTRING



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INSPECT Specifies that characters or group of characters in adata item are to be countered or (tallied) or replacesor both

Counts all the occurrences of a specific character

Will fill all portions of data item with specifiedcharacters such as spaces or zeros

Will convert all occurrences of specific characters ina data item to user supplied replacement character

INSPECT IDENTIFIER1TALLYINGIDENTIFIER2

FOR[ALL/LEADING][IDENTIFIER3/LITERAL1] [PHRASE]

[PHRASE] here is AFTER/ BEFORE[INITIAL] IDENTIFIER4/LITERAL2.



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INSPECT

INSPECT IDENTIFIER1REPLACINGCHARACTERS

BY [IDENTIFIER2/LITERAL1]BEFORE/AFTERINITIAL [IDENTIFIER3 /

LITERA

L 2]A

FTER

/ LEA

DING/FIRST

[IDENTIFIER/LITERAL.]By IDENTIFIER/LITERAL [PHRASE]PHRASE] here is AFTER/ BEFORE

[INITIAL] IDENTIFIER4/LITERAL2.

DECLARATIVESDECLARATIVES


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Used for tracing the paragraph or procedure executedby the program as per the instruction given by theprogrammer

WITH DEBUGGING MODE option has to be specifiedin the OBJECT-C0MPUTER paragraph

Has to be first section in PROCEDURE DIVISION

PROCEDURE DIVISION.

DECLARATIVES.DEBUG -DECLARATIVES SECTION.USE FOR DEBUGGING ALL PROCEDURE .DEBUG -DECLARATIVES -PARA.DISPLAY TRACING DEBUG-NAME

END DECLARATIVES.

SORT STATEMENTSORT STATEMENT


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Accepts records from on or more files and arranges the records

in the ascending/descending order and makes sorted recordsavailable either through an OUTPUT-PROCEDURE or in anoutput file.

Can be appeared anywhere in PROCEDURE DIVISION

SORT file-name-1ON[ASCENDING/DESCENDING KEY]data-name-1[WITH DUPLICATES ] [IN ORDERCOLLATING SEQUENCE ISAlphabet- name-1]

INPUT PROCEDURE IS procedure-name-1THRU procedure-name-2OUTPUT-PROCEDURE IS procedure-name- 3THRU procedure-name-4

END-SORT.



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File-name -1 is the name given in the SD entry that describes

the records to be sorted

data-name-1 specifies a KEY data item on which the SORTstatement will be based

Each data name must identify a data item in a recordassociated with file-name -1

Alphabet-name1 must be specified in the alphabet clause ofSPECIAL-NAMES para

USING and INPUT-PROCEDURE are mutually exclusive

Input-Procedure is specified to Select or Modify the InputRecord before Sort

This Procedure can do any modifications in the record and copyUsing RELEASE Statement

GIVING and OUTPUT-PROCEDURE are mutually exclusive



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Output-Procedure is specified to Select or Modify the output

Record After Sort

This Procedure can do any modifications in the record and copyUsing RETURN Statement

MERGE STATEMENTMERGE STATEMENT


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Merges two or more input files based on common key.

The merged records are made available to an output file or toan output procedure

MERGE file-name-1ON [ASCENDING/DESCENDING KEY]data-name-1 USING file-name-2 file-name-3

[COLLATING SEQUENCE ISAlphabet-name-1]GIVING file-name-4 /OUTPUT-PROCEDURE IS procedure-name-3THRUprocedure-name-4

File-name -1 is the name given in the SD entry that describes

the records to be merged

GIVING and OUTPUT-PROCEDURE are mutually exclusive

INTRINSIC FUNTIONSINTRINSIC FUNTIONS


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NUMBER HANDLING

LENGTH Returns the length of the Picture clause

FUNCTION LENGTH(NAME)

MAX Returns the content of the argument that containsthe maximum value

FUNCTION MAX(MARKS) MIN Returns the content of the argument that contains

the minimum value

FUNCTION MIN(MARKS)

NUMVAL Returns the numeric value represented by the

alphanumeric character string specified in the argument

DATEDATE -- TIMETIME


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CURRENT DATE

Returns 21 characters alphanumeric value

1..4 Year in the Gregorian calendar

5,6 Month of the year

7,8 Day of the Month

9..14 HHMMSS and so on

DATE-OF-INTERGER

Converts a date in the Gregorian calendar from integerdate form to standard date form yyyymmdd

DAY-OF-INTEGER Converts a date in the Gregorian calendar from integerdate form to Julian date form yyyymmdd

COMPILER OPTIONSCOMPILER OPTIONS


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NOC

Specified to do only Syntax check

NOC (W), NOC (E), NOC (S)

W is warning, E is for error and S for severe. When anerror level of specified or of a more severe level occurs,compilation stops.

Default is S

DYNAM

Causes subprograms that are invoked through the CALLliteral statement to load dynamically

NODYNAM

Causes the text files of subprograms called with a CALLliteral statement to be included with the calling program intoa single module file

ERROR CODESERROR CODES


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File Status will have Picture clause of length 2 digits

The first digit denotes general category under which theerror code falls

The second digit will denote the particular type of errorunder that category

The first digit categories are:0 Returned When Successful Open / Read / Write /

Operation.1 Returned When At End Condition Fails2 Returned When Index Key Fails3 Returned When Permanent Open Error Occurs.4 Returned When Logic Error in

opening/closing/deleting etc9 Implementer Defined

ERROR CODESERROR CODES


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00 - Successful completion

02 - Duplicate key detected

10 - Sequential READ was attempted on an optional file thatwas not present or after end of file is reached

21 A sequence error exists for a sequentially accessedindexed file

39 - An OPEN statement was unsuccessful because of aconflict between the fixed file attributes and theattributes specified for the file in the program


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03-23-0530 Sept 2005

EDS

RMZ Millenia Business Park

Chennai 600113

91 44 6612 2358

harinath munupalle@eds com

Presentation by Harinath M.

Eds Cobol Training

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