IBM Mainframe - Cobol Material

5/28/2018 IBM Mainframe - Cobol Material

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CopyrightCourse materials may not be produced in whole or in part

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Table of Contents

UNIT 1. Introduction to Language Features

COMMON BUSINESS ORIENTED LANGUAGECOBOL PROGRAM ORGANIZATION

COBOL LANGUAGE STRUCTURESTRUCTURE OF COBOL PROGRAM

CHARACTER SET OF COBOLSAMPLE COBOL PROGRAM

CODING FORMATUSER-DEFINED WORDS

UNIT 2. The Organization of a COBOL Program

IDENTIFICATION DIVISION

ENVIRONMENT DIVISIONDATA DIVISIONDATA-ITEMS

LEVEL NUMBERSSPECIAL LEVEL NUMBERS

W-S DECLARATIONSFILLER

PICTURE CLAUSEUSAGE CLAUSE

VALUE CLAUSEREDEFINES CLAUSE

DUPLICATE DATA NAMESRENAMES CLAUSE

FIGURATIVE CONSTANTSEDITED FIELDS

MORE EDITING CHARACTEREXAMPLES

UNIT 3. PROCEDURE DIVISIONPROCEDURE DIVISION

COBOL VERBSPARAGRAPHS

TERMINATOR STATEMENTSSCOPE TERMINATORS

DISPLAY VERBACCEPT VERB

MOVE VERBELEMENTARY & GROUP MOVES

CORRESPONDING PHASEREFERENCE MODIFICATION


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ADD VERB

ADD CORRESPONDING STATEMENTON SIZE ERROR PHRASE

NUMERIC DATA

SUBTRACT VERBSUBTRACT CORRESPONDING STATEMENTMULTIPLY VERB

DIVIDE VERBCOMPUTE STATEMENT

PERFORM STATEMENTPERFORM THROUGH

PERFORMN TIMESPERFORMVARYING

IN-LINE PERFORMRELATIONAL EXPRESSIONS

IF STATEMENTCOMPOUND CONDITIONALS

CLASS CONDITIONCONTINUE & NEXT SENTENCE STATEMENT

EVALUATE STATEMENTSET TO TRUE

INITIALIZE

UNIT 4. FILE HANDLING IN COBOLFILES

FIXED VS VARIABLE LENGTH RECORDS

FILE-CONTROL PARAGRAPHACCESS MODEFILE STATUS CLAUSE

I-O CONTROL PARAGRAPHFILE SECTION

FILE OPERATIONSOPEN MODES

READ-SEQUENTIAL ACCESSEND OF FILE PROCESSING

READ RANDOM ACCESSREAD DYNAMIC ACCESS

START STATEMENTWRITE STATEMENT

WRITEFROMREADINTO

REWRITE & DELETEAPPENDING TO SEQUENTIAL FILES

FILE COMPARISONCLOSE STATEMENT


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SEQUENTIAL FILES

INDEXED FILESINVALID KEY

ACCESS MODE: SEQUENTIAL & RANDOM

ACCESS MODE: DYNAMICRELATIVE FILES

UNIT 5. TABLE HANDLINGINTRODUCTION: TABLE HANDLING

OCCURS CLAUSESUBSCRIPT

INDEXINGONE DIMENSIONAL TABLE

TWO DIMENSIONAL TABLEMULTIDIMENTIONAL TABLE

TABLE-SORTINGSET

SEARCHBINARY SEARCH

UNIT 6. Library ServicesCOPY STATEMENTNESTED COPY

COPY REPLACINGCOPY PSEUDO-TEST

REPLACE PSEUDO-TEST

UNIT 7. CHARACTER HANDLINGSTRING

UNSTRING STATEMENTEXAMINE STATEMENT

INSPECT TALLYING STATEMENTINSPECT REPLACING STATEMENT

UNIT 8. SORT / MERGESORT/MERGESORT STATEMENT

MERGE STATEMENTSORT PROCEDURES

RELEASE STATEMENTRETURN STATEMENT

Cobol Lab


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UNIT 1

Introduction To Language Features


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Common Business Oriented Language

1959 New Language is named COBOL 1960 Codasyl established COBOL maintenance committee

(Conference on data system language).

1961 1st version of complier made available. Users startedwriting programs (1962).

1968 2nd version of cobol was approved and standardized byANSI

1974 Revised and released as COBOL-74 1985- Revised and released as COBOL-85

Notes:

To meet the increasing demands for a high level language suitable for business

data processing, the United States Department of Defense Convened a

Conference on 28thand 29thof May 1958.

Three committee were formed for the actual design of the language.

In September 1959 the short term committee submitted a report to the Defense

Directorate thus COBOL came into existence.

COBOL is known as a structured programming language because it allows

programmers to segregate the modules and put them into different paragraphs in

a more efficient way.

Some of the features of COBOL are It is English-like and more easily readable Efficient file handling capabilities. More than 70% of business applications are running on COBOL Reduces the efforts required for documentation of the program.

The following features are available with VS COBOL II:


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MVS/XA and MVS/ESA support The compiler and the object programs it produces can be run in either 24- or 31-bit addressing mode


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COBOL Program Organization

The basic structure of any cobol program contains four divisions namely:


ENVIRONMENT DIVISION

DATA DIVISION

PROCEDURE DIVISION

Every cobol program must have these divisions.

Notes:

The four divisions of a COBOL source program are :

IDENTIFICATION DIVISIONThe primary purpose of these program is to name the program.

ENVIRONMENT DIVISIONThis division is primarily used to tell the computer about the input and

output devices such as files or printers.

DATA DIVISION


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The division is used to define and describe the data items and being used

in the program. Data items and data names refer to some storage space in

memory to store data. Here you would distinguish between data, which

will be used for a scratch pad area called WORKING-STORAGE and

the holding area for data that will be used by the files.

PROCEDURE DIVISIONThe PROCEDURE DIVISION is the section of our program where the

logic or commands reside. This is also the place logic or rules we will use

to manipulate the data defined in the DATA DIVISION to solve a

business problem.


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Cobol Language Structure

Characters

Character String COBOL Words User-Defined Words Reserved Words Figurative Words Special Registers

IBM Extensions Non-numeric and numeric Literals

Notes:


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Structure of a Cobol Program

Examples

Divisions DATA DIVISION

Sections or Paragraphs PROGRAM-ID

FILE SECTION, 100-PARA

Statements MOVE A TO B

Sentences IF A>B MOVE A TO B ELSEADD C TO D

Notes:

All COBOL programs should follow the structure. Rules of coding varies,

depending on the compiler versions but the structure remains same. A period (.)

is a must at the end of each sentence and indicates the end of the sentence.

A typical program could contain divisions, sections or paragraphs within

divisions, and statements within sections or paragraphs. There are both systemand user defined sections and paragraphs.

Eg: PROCEDURE DIVISION.

ADD-PARA.

ADD A,B GIVING C.

SUB-PARA.

Where A,B and C are dada items defined in the data divisions.


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Character Set of COBOL

COBOL supports the following characters

Numbers : 0-9 (10 Numericals)

Alphabets : a-z, A-Z (26 English letters)

Spaces or blanks : Some times denoted by blanks

Arithmetic operators : ex: **, *, +, -, /

Special characters : ex: - \ / , ;

Notes:

The character 0-9 are called numeric characters or digits.

The characters A-Z are called letters and remaining are called special characters.

The COBOL dictionary words used for coding are called COBOL reserved words

and they should not be used as user-defined words.

Lower case alphabets can be used for coding depending on the compiler version.

Comma (,) or space is used as separators for user-defined words.


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Sample COBOL Program

Notes:

1-6 -------------- Sequence numbers

7 -------------- Indicator/Comment/Continuation

8-11 -------------- Area A

12-72 -------------- Area B

73-80 -------------- Descriptor

This foil shows a sample COBOL program to ADD two numbers and

DISPLAY the sum. SAMPLE is the program name.

SAMPLE, A, B AND C are called user-defined words.

A, B,C are called variables or data-items.

Columns

1 6 7 8 11 12 72 73 80

* This is a sample program

IDENTIFICATION DIVISION.

PROGRAM-ID. SAMPLE.

ENVIRONMENT DIVISION.

DATA DIVISION.

WORKING-STORAGE SECTION.01 A PIC 9(2) VALUE 20.

01 B PIC 9(2) VALUE 3O.

01 C PIC 9(3) VALUE ZEROS.

PROCEDURE DIVISION.

DISPLAY THE SUM IS.

ADD A ,B GIVING C.

DISPLAY C.

STOP RUN.


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Coding Format

01 06 Sequence Sequence numbers are generated by

cobol compiler for each line

07 Indicator To mark an asterisk (*) or a slash (/)

for comment line, or a hyphen (-) for

continuation of a statement.

08 11 Area A All division headings, section and

paragraph headings and 01 level

entries should begin from this area.

12 72 Area B All Cobol statements and sentences

should lie within this area

73 80 Description Any thing written in this area is

ignored.

Notes:

COBOL coding should follow the standard format.

The Screen is divided into different areas for the purposes explained above.

All statements indicating action are called COBOL verbs and should begin from

12th

column or after.

-E.g MOVE, ADD, DIVIDE, STOP RUN


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User-defined Words

Valid Invalid Reason

TOTAL-OF-FIGURES DATA Cobol reserved word

34B100-PARA1 -48B Hyphen in beginning

GROSS-PAY GROSS PAY space in b/w 2 words

Literals Examples

Numeric constants 35, -345.67Alphanumeric constants Leo talstoy

ka01-h215

Paragraph names, Identifiers, File names can be defined byusers.

The terms identifiers, data-names, variables, data-items are oftenused interchangeably indicates memory.

Notes:

All user-defined words should conform to following rules:

Length should not exceed 30 characters.

At least one character must be an alphabet. Spaces and special characters are not allowed. Word can contain hyphens (-) but not in the beginning or at the end Cannot be a COBOL reserved word.


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UNIT 2

The Organization of a COBOL Program


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Notes:

The Identification Division must be the first division in every COBOL source

program. It must be coded as IDENTIFICATION DIVISION or ID DIVISIONfollowed by a separator period.

The Identification Division identifies the source program and the resultant outputlisting. The user can include the date the program is written and other information asdesired under the paragraphs in the general format. This entire division (includingthe division header) is optional.

IDENTIFICATION DIVISION.PROGRAM-ID. AUTHOR. DATE WRITTEN. DATE-COMPILED. SECURITY.

RequiredRequiredOptionalOptionalOptionalOptional

At least one space required after the period


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ENVIRONMENT DIVISION

ENVIRONMENT DIVISION.

CONFIGURATION SECTION.SOURCE-COMPUTER. .

OBJECT-COMPUTER. .

INPUT-OUTPUT SECTION.

FILE-CONTROL.

----------------------------

----------------------------

I-O-CONTROL.

-----------------------------

-----------------------------

Notes:

The Environment Division is divided into two sections:

The CONFIGURATION SECTIONThe Configuration Section is an optional section for programs which describe thecomputer environment on which the program is compiled and executed.

The Configuration Section can be specified only in the ENVIRONMENTDIVISION of the outermost program of a COBOL source program.

The INPUT-OUTPUT SECTIONThe Input-Output Section of the Environment Division contains two paragraphs:

o FILE-CONTROL paragrapho I-O-CONTROL paragraph

FILE-CONTROL paragraphThe keyword FILE-CONTROL can appear only once, at the beginning of the

FILE-CONTROL paragraph. It must begin in Area A, and be followed by aseparator period. The FILE-CONTROL paragraph is optional.

The FILE-CONTROL paragraph associates each file in the COBOL program withan external data set, and specifies file organization, access mode, and otherinformation.


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There are three formats for the FILE-CONTROL paragraph:

QSAM, SAM, and VSAM sequential file entries VSAM indexed file entries VSAM relative file entries.

The FILE-CONTROL paragraph begins with the word "FILE-CONTROL",followed by a separator period. It must contain one and only one entry foreach file described in an FD or SD entry in the Data Division. Within eachentry, the SELECT clause must appear first, followed by the ASSIGN clause.The other clauses can appear in any order.

I-O-CONTROL paragraphSpecifies information needed for efficient transmission of data between the

external data set and the COBOL program. The series of entries must end witha separator period

The keyword I-O-CONTROL can appear only once, at the beginning of theparagraph. The word I-O-CONTROL must begin in Area A, and must befollowed by a separator period.

Each clause within the paragraph can be separated from the next by a separatorcomma or a separator semicolon. The order in which I-O-CONTROL

paragraph clauses are written is not significant


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DATA DIVISION

Data division is the third and most frequently used division in all

programs. Every data items or variable required by the program shouldbe declared in appropriate section of the data division, before using in

procedure division. The Data Division is divided into three sections:

File Section:

Defines the structure of data files (including sort-merge files). If the

program is accessing files.

Working-Storage Section:

Describes records and subordinate data items that are not part of

data files but are required by the program.

Linkage Section:

Describes data made available by another program. It usually

appears in the called program and describes data items that are referred

to by the calling and the called programs.

Each section has a specific logical function within a COBOL source

program, and each can be omitted from the source program when that

logical function is not needed. If included, the sections must be written inthe order shown.


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DATA DIVISION.FILE SECTION.FD . ---------------

---------------WORKING-STORAGE SECTION. DATA TYPES01 VAR-1 PIC A(5). -Alphabetic01 ID-1 PIC X(10) -Alphanumeric01 DATA-NAME PIC 9(5) -Numeric

Level number pictureClause data type (length)

LINKAGE SECTION.record-description-entrydata-item-description-entry


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DATA-ITEMS

Explicitly identifies the data being described

The data-item must be the first word following the level-number.

The data-item values can be changed during program execution.

A data-item name cannot be the same as a section-name or aparagraph name

Notes:

Data item is a user-defined word which is associated with Level number.

COBOL Reserved words should not be Data items.

The data division of a COBOL source program describes, in a structured manner, allthe data to be processed by the program.

This division allocates memory locations for the data items that a program requires.There are several types of storage locations in COBOL: file buffers, misc. scratchdata, communication buffers, screen paint data and report format data.


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Level Numbers

Range of level numbers available are 01 to 49 and

66 level specified for RENAMING CLAUSE

77 levels specified exclusively for elementary items

88 levels specified for CONDITION NAMES.

An elementary item can be declared with level numbers 01 and 77

01 and 77 level entries must begin from area A and other levelentries can begin from any where in area A or area B

Notes:

Level represents the nature of a data item.

The level-number specifies the hierarchy of data within a record, and identifiesspecial-purpose data entries. A level-number begins a data description entry, arenamed or redefined item, or a condition-name entry. A level-number has a valuetaken from the set of integers between 01 and 49, or from one of the special level-numbers, 66, 77, or 88.

Level-number 01 and 77 must begin in Area A and must be followed either by aseparator period; or by a space, followed by its associated data-name, FILLER, orappropriate data description clause.


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Level numbers 02 through 49 can begin in Areas A or B and must be followed by aspace or a separator period.Level number 66 and 88 can begin in Areas A or B and must be followed by a space.

Single-digit level-numbers 1 through 9 can be substituted for level-numbers 01

through 09.

Successive data description entries can start in the same column as the first or theycan be indented according to the level-number. Indentation does not affect themagnitude of a level-number.

When level-numbers are indented, each new level-number can begin any number ofspaces to the right of Area A. The extend of indentation to the right is limited only

by the width of Area B.

Higher numbered level(s) represent subordinate definition(s).

Level numbers need not be consecutive (but should be in ascending order)


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Special Level Numbers

LEVEL-66 Identifies items that must contain a RENAMES clause;such items regroup previously defined data items.

LEVEL-77 Identifies data item description entries that areindependent working-storage, local-storage, or linkage section items;

they are not subdivisions of other items and are not subdivided

themselves. Level-77 items must begin in Area A.

LEVEL-88 identifies any condition-name entry that is associatedwith a particular value of a conditional variable.

Notes:

LEVEL-66regroups previously defined items.

A level-66 entry cannot rename another level-66 entry, nor can it rename a level-01,level-77, or level-88 entry.

All level-66 entries associated with one record must immediately follow the last data

description entry in that record.

LEVEL-77 items are ELEMENATARY items with no subdivision. LEVEL-77names are unique because they can not be qualified.

LEVEL-88describes condition-names.LEVEL-88 can be used to describe both elementary and group items.

Level-77 and level-01 entries in the working-storage, local-storage, and linkagesections that are referenced in a program or method must be given unique data-

names because level-77 and level-01 entries cannot be qualified. Subordinate data-names that are referenced in the program or method must be either uniquely defined,or made unique through qualification. Unreferenced data-names need not beuniquely defined.


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Picture Clause

Describes the characteristics of the data

CODE meaning

A alphabetic or spaceB Blanks or spacesG or N Graphical data9 Indicates a NumericX Indicates an Alpha NumericP Indicates the position of the assumed

decimal point when the point lies outsidethe data item.V Indicates the position of assumed decimal

point of numeric field.S Indicates whether the data item signed.

Notes:

Picture clause specifies the data type of an identifier.

Identifier with PIC clause 9 implies that it is numeric data type, which can takeart in arithmetic computations. V and S clauses are allowed with numeric datatypes only.

X clause represents an alphanumeric data type which can hold any characterincluding numbers also.

A clause indicates an alphabetic data type.

Group items are always considered as alphanumeric only. Therefore GROSS-PAY,DEDUCTIONS can not be used for computations.


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W-S Declarations

WOKING-STORAGE SECTION.

01 PAY.

05 GROSS-PAY. Alternatively

10 BASIC PIC 9(4)V99.

10 DA PIC 9(4)V99. 9(4)V9(2)

10 HRA PIC 9(4)V99 9999V99

05 DEDUCTIONS.

07 PF-DED PIC 9(3)V99.

07 IT-DED PIC 9(3)V99.

05 NET-PAY PIC 9(4)V99.

05 NAME PIC A(5). AAAAA

05 E-CODE PIC X(6). XXXXXX

Notes:

Use the WORKING-STORAGE SECTION in the DATA DIVISION of theOBJECT paragraph to describe the instance datathat a COBOL class needs, that is,

the data to be allocated for each instance of the class. The OBJECT keyword, whichyou must immediately precede with an IDENTIFICATION DIVISION declaration,indicates the beginning of the definitions of the instance data and instance methodsfor the class.

Pay, gross-pay, deductions are called group items and they dont have PICTUREclause. Other elements with picture clause are called elementary items, which cannot

be broken further.

Pay is a Group item is divided into Gross-pay, Deductions, net-pay, name, e-codefurther Gross-pay sub-divided into Basic, DA, HRA and DEDUCTIONS sub-divided into PF-DED and IT-DED.


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FILLER

FILLER is a COBOL Reserved Word used to describe data fields that

will not be referenced in the PROCEDURE DIVISION.

If the data-name of FILLER clause is omitted, the data item being

described is treated as though it was FILLER

01 EMPLOYEE-RECORD.

05 EMPLOYEE-TYPE PIC X.

05 EMPLOYEE-SERIAL PIC X(6).

05 EMPLOYEE-NAME PIC X(30).PIC X(2).

05 EMPLOYEE-ADDRESS PIC X(60).

05 FILLER PIC X(34).

Notes:

FILLER is a data item that is not explicitly referred to in a program. The key wordFILLER is optional. If specified, FILLER must be the first word following the level-number.

IF data-name or FILLER clause is omitted, the data item being described is treatedas though FILLER had been specified.

The VALUE clause may be used on FILLER items, e.g. to assure BLANKS inheader lines between fields.

In a MOVE CORRESPONDING statement, or in an ADD CORRESPONDING orSUBTRACT CORRESPONDING statement, FILLER items are ignored.

In an INITIALIZE statement, elementary FILLER items are ignored.


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USAGE Clause

data-name [PIC X(n)] [USAGE] COMPCOMP-1

COMP-2COMP-3

COMP - Binary Representation Size: Half/Full/Double word

COMP-1 - Hexa Decimal Representation Size: Full word for Float

COMP-2 - Hexa Decimal Representation Size: Double word for Float

COMP-3 - Packed Decimal Representation Size: round(n/2)+1Where n is number of digits.

Notes:

The usage description must match the data-field type described in the FD descriptor

of the COBOL program. If the COBOL program does not include a usage clause,select the Chars (character) option for the usage.

The USAGE clause can be specified for a data description entry with a level-numberother than 66 or 88. However, if it is specified at the group level, it applies to eachElementary item in the group. The usage of an elementary item must not contradictthe usage of a group to which the elementary item belongs.

The USAGE clause specifies the format in which data is represented in storage. Theformat can be restricted if certain Procedure Division statements are used.

When the USAGE clause is not specified at either the group or elementary level, itassumed that the usage is DISPLAY.


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Computational (COMP) Usage

When usage is specified as COMP, the numeric data item is represented in pure binary. Theitem must be an integer (no assumed decimal point is allowed). Such that data items areoften used as subscripts. The PICTURE of a COMP item should not contain any character

other than 9, S. This is the equivalent of BINARY. The COMPUTATIONAL phrase issynonymous with BINARY.

COMPUTATIONAL-1 (COMP-1) Usage

If the usage of a numeric data item is specified as COMP-1, it will be represented in oneword in the floating point form. The number is actually represented in Hexa decimal (base16). Such representation is suitable for arithmetic operations. The PICTURE clause cannotbe specified for COMP-1 items. Specified for internal floating-point items (singleprecision). COMP-1 items are 4 bytes long.

COMPUTATIONAL-2(COMP-2) Usage

This usage is same as COMP-1, except that the data is represented internally in two words.The advantage is that this increases the precision of the data which means that moresignificant digits can be available for the item. The PICTURE clause cannot be specified forCOMP-2 items. Specified for internal floating-point items (double precision). COMP-2items are 8 bytes long.

COMPUTATIONAL-3(COMP-3) Usage

In this form of internal representation the numeric data is the decimal form, but one digittakes half-a-byte. The sign is stored separately as the right most half a-byte regardless ofwhether S is specified in the PICTURE or not. The hexa decimal number C or F denotes apositive sign and the Hexa decimal number D denotes a negative sign. Inorder that datafields can start and end on byte boundaries, numbers with an even number of digits arestored with an extra half-byte of zeroes on the left hand side. Thus an item with

PICTURE S9(5)V9(3) USAGE IS COMP-3

will require 5 bytes to be stored internally. Only the characters 9, S, V and P can be used inthe PICTURE of a COMP-3 item. This is the equivalent of PACKED-DECIMAL.


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Value Clause

Value Clause defines the initial value of a data item must not be used for

items declared in FILE SECTION. Can also specify FIGURATIVECONSTANTS. If defined at the group level can be used for array

declaration also

EXAMPLES

01 NUM-1 PIC 9(3) VALUE 245.

01 E-CODE PIC X(6) VALUE E10K3.

At group level contents01 GROUP-ITEM VALUE IS ER34155

05 E-ITEM-1 PIC X(2). ER

05 E-ITEM-2 PIC XXX 341

05 E-ITEM-3 PIC X(3) 55

Group item is considered as alphanumeric.

Notes:

Assigning values to identifiers is called initialization. If variables are not initialized,then they may contain any value, which was stored at the time of last execution of

program. It is advised to always initialize working-storage variables.

The VALUE clause specifies the initial contents of a data item or the valuesassociated with a condition-name. The use of the VALUE clause differs dependingon the data division section in which it is specified.

A VALUE clause that is used in the file section or the linkage section in an entryother than a condition-name entry is syntax checked, but has no effect on the

execution of the program.

In the working-storage section and the local-storage section, the VALUE clause canbe used in condition-name entries or in specifying the initial value of any data item.The data item assumes the specified value at the beginning of program execution. Ifthe initial value is not explicitly specified, the value is unpredictable.


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REDEFINES Clause

Two or more data items can share the same working storage area by

REDEFINING a storage area.

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

Level numbers of data-name-1 and data-name-2 must be identical

The redefines clause must immediately follow data-name-I

Must not be used for level number 66 or 88 items.

Data-name-1 should not contain VALUE clause

Multiple redefinition is allowed

Notes:

Two or more storage areas defined in the data sometimes may not be usedsimultaneously, in such cases; only one storage area can serve the purpose oftwo or more areas if the area is defined.

The REDEFINES clause used allows the said area to be referred to by morethan one data name with different sizes and pictures.

ILLUSTRATES REDEFINES CLAUSE


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DATA DIVISION.

WORKING-STORAGE SECTION.

01 X1

02 Y PIC 99.

02 Y1 REDEFINES Y PIC XX.

01 X3

02 Z PIC X VALUE M.

02 ZZ PIC X (25) VALUE ALL *.

02 ZZZ PIC X (45) VALUE ALL - .

01 X4 REDEFINES X3.

02 FILL1 PIC X.

02 FILL2 PIC X (70).01 X5 REDEFINES X4.

02 BUFFER PIC X (71).

PROCEDURE DIVISION

PARA 1.

MOVE 20 TO Y.

DISPLAY X1.

MOVE A1 TO Y1.

DISPLAY X1

DISPLAY X3.

DISPLAY X4.

DISPLAY X5.

STOP RUN.

Duplicate Data Names


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Are allowed, provided they belong to a group item

01 Pay-Rec.

02 Id-numbers PIC 9(5).

02 Name PIC X (25).

02 Dept PIC X (20).

01 Print-Rec.

02 Filler PIC X (5).

02 Id-numbers PIC X (5)

02 Filler PIC X (5).

02 Name PIC X (25).

02 Dept PIC X (920).

MOVE Id-Numbers (OF | IN) Pay-Rec TO Id-Numbers (OF | IN)Print-

Rec.

* OF and IN are called Qualifiers.

To move the data stored in the four fields of Pay-Rec. the four MOVEstatements serve the purpose.

Using the MOVE CORRESPONDING statement the same can beaccomplished.

RENAMES Clause

Syntax:


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66 data-name-1 RENAMES data-name-2 THRU data-name-3

E.g. :

01 PAY REC.

02 FIXED-PAY.05 BASIC PIC 9(6) V99.

05 DA PIC 9(6) V99.

02 ADDITIONAL-PAY.

05 HRD PIC 9(4) V99.

05 INCENT PIC 9(3) V99.

02 DEDUCTIONS.

05 PF PIC 9(3) V99.

05 IT PIC 9(4) V99.

05 OTHER PIC 9(3) V99.

66 PAY-OTHER-THAN-BASIC RENAMES DA THRU INCENT.

66 IT-AND-PF-DEDUCTIONS RENAMES PF THRU IT.

Notes:

In order to re-group elementary data items in a record, so that they can belong to theoriginal as well as to the new group, the RENAMES clause is used.

The RENAMES clause specifies alternative and possibly overlapping groupings ofelementary data items.

LEVEL-66regroups previously defined items.

A level-66 entry cannot rename another level-66 entry, nor can it rename a level-01,level-77, or level-88 entry.

All level-66 entries associated with one record must immediately follow the last datadescription entry in that record.

ILLUSTRATES RENAMES CLAUSE

DATE DIVISION.


01 PAY


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02 FIXED-PAY

10 E-BASIC PIC 9(6). 99

10 E-DA PIC 9(6). 99.

05 ADDL-PAY.

10 HRA PIC 9(4). 99.

10 INCENTIVE PIC 9(3). 99.

05 DEDUCTIONS.

10 E-PF PIC 9(3). 99.

10 E-IT PIC 9(4). 99.

10 OTHERS PIC 9(3). 99.

66 PAY-LESS-BASIC RENAMES E-DA THRU INCENTIVE.

66 IT-AND-PF RENAMES E-PF THRU E-IT.

PROCEDURE DIVISION.

MAIN-PARA

MOVE-123456.78 TO E-BASIC.

MOVE 234567.89 TO E-DA.

MOVE 1234.56 TO HRA.

MOVE 123.45 TO INCENTIVE.

MOVE 123.45 TO E-PF.

MOVE 1234.56 TO E-IT.

MOVE 123.45 TO OTHERS.

DISPLAY PAY.

DISPLAY FIXED-PAY.DISPLAY ADDL-PAY.

DISPLAY DEDUCTIONS.

DISPLAY PAY-LESS-BASIC.

DISPLAY IT-AND-PF.

STOP RUN.

Figurative Constants

Constants frequently used by most programs


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Collating sequence is the order in which the characters arecompared by the system.

Figurative Constants Meaning

HIGH-VALUE(S) Represents the highest and lowest

LOW-VALUES (S) value in the collating sequence.

ZERO, ZEROS, ZEROES One or more Zeroes

SPACE (S) One or more blanks

Example: 01 ID-1 PIC X(3) VALUE SPACES.

Notes:

Figurative constants are reserved words that name and refer to specific constantvalues.

ZERO, ZEROS, ZEROES:

Represents the numeric value zero (0) or one or more occurrences of the characterzero, depending on context. When the figurative constant ZERO, ZEROS, orZEROES is used in a context that requires an alphanumeric character, analphanumeric character zero is used.

SPACE:

Represents one or more blanks or spaces. SPACE is treated as an alphanumericliteral when used in a context that requires an alphanumeric character, as a DBCSliteral when used in a context that requires a DBCS character, and as a nationalliteral when used in a context that requires a national character.

HIGH-VALUE:

Represents one or more occurrences of the character that has the highest ordinalposition in the collating sequence used. HIGH-VALUE is treated as an alphanumericliteral in a context that requires an alphanumeric character.


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LOW-VALUE:

Represents one or more occurrences of the character that has the lowest ordinalposition in the collating sequence used. LOW-VALUE is treated as an alphanumeric

literal in a context that requires an alphanumeric character.

Edited Fields

Move 345.46 to a field of picture 9(3)v99 & display or print Youmay see different number in result


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Characters must be edited before report is taken to suppressleading zeros, to include currency signs or to include date

separators.

Editing Codes Effect

Z Leading Zeros if any will be suppressed

* Leading Zeros are replaced by asterisks(*)

$ Currency sign appears in the left most of

the field.- Appears at left or right of the field as

specified in the picture clause if value is

negative

+ Appears if value is positive, else minus sign

appears

Editing Codes are specified in the picture clause for variables intended for

report purpose.

These variables cannot be used for arithmetic calculations.

More Editing Characters

EDIT CODES Meaning


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CR or DB To be specified in the right most position of

the pic clause. Appears only if the value is

negative it replaced by two characters.

. Stands for decimal point. Cannot specify

with V clasue.

, Insert in position where specified.

B Blank is appeared.

0 Zero is also appeared. To be specified left

most position of pic clasue.

- (hyphen) /(slash) Used as date separator. Appears wherespecified.

BLANK WHEN ZERO Sets all null values to blanks.

EXAMPLES

DATAPIC CLAUSEUNEDITED

PIC CLAUSEEDITED

EDITEDVALUE

02346 9(5) ZZ999 2346

0005 9(4) ZZ99 05


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03.42 99V99 Z999 003

0.007 9V999 ZV999 007

05634 9(5) **999 *5634

00143 9(5) $9(5) $00143

453 9(3) $**999 $**453-0453 9(4) -ZZ9(2) -453

-0453 9(4) 9999- 0453-

453 9(3) 999- 453

-453 9(3) 999+ 453-

70.46 99V99 99.99- 70.46

156758 9(6) 99/99/99 15/67/58

00 99V9 99.9 Blank whenzero

8654 9(4) 99b9b9 86b5b424 99 9900 2400

Notes:

The above table shows contents of unedited fields in the first column. Contents ofedited fields after moving the data-1 shown in last column.

Edited fields (Fields with editing codes) cannot take part in arithmetic computations.

Moving of numeric edited fields to unedited fields is illegal.


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UNIT 3

PROCEDURE DIVISION


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PROCEDURE DIVISION

PROCEDURE DIVISION[USING , .

MAIN-PARA.

DISPLAY ENTER VALUE OF A:.ACCEPT A.

DISPLAY ENTER VALUE OF B:.

ACCEPT A.

MOVE A TO B.

ADD A TO B.

DISPLAY A VALUE : A.

DISPLAY B VALUE : B.

---------------------------------

--------------------------------

STOP RUN.

Notes:

Procedure Division can consists ofSections (Optional)Paragraphs (Optional)Statements.

While coding, we must follow the following Hierarchy:SECTION------- PARAGRAPHS ------STATEMENTS

OrPARAGRAPH------- STATEMENTS

OrSTATEMENTS


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COBOL VERBS

All instructions are coded in Procedure division.

BASIC COBOL VERBS

MOVE ACCEPT DISPLAY PERFORM GO TO STOP RUN CALL COPY SORT MERGE FILE OPERATIONS CHARACTER HANDLING TABLE HANDLING CONDITIONS ARITHMETIC VERBS

Notes:

Arithmetic Verbs : ADD, SUBTRACT, MULTIPLY, DIVIDE, COMPUTEConditions : IF.ELSE, EVALUATEFile handling : READ, WRITE, REWRITE, DELETECharacter handling : INSPECT, STRING, UNSTRINGTable handling : SET, SEARCH

Paragraphs

Paragraphs are building blocks of the PROCEDURE DIVISION


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PROCEDURE DIVISION.

MAIN-PARA.

STATEMENT1.

STATEMENT2.

------------------------------------------

---------------------

PARA-100.

---------------------

---------------------

Notes:

A paragraph-name must begin in Area A and must be followed by a separatorperiod.

A paragraph-name need not be unique because it can qualified by a SECTIONname.

Paragraph-names need NOT contain any alphabetic character (i.e. can be allnumeric).

A paragraph ends at:

The next paragraph-name or section header The end of the PROCEDURE DIVISION The Scope terminator END-PARAGRAPH

Terminator Statements

EXIT PROGRAM


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The EXIT PROGRAM statement specifies the end of a called program

and returns control to the calling program

STOP RUN

The STOP RUN statements halts the execution of the object program,

and returns control to the system

GOBACK

The GOBACK statement functions like the EXIT PROGRAM

statement. When it is coded as part of a called program and like the

STOP RUN when coded in a main program

Notes:

If these statements are not the last statements in a sequence, statements following

them will not be executed.

Scope Terminators

Explicit scope terminators mark the end of certain PROCEDURE

DIVISION statements.

Explicit scope terminators are COBOL Reserved Words.


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END-ADD

END-SEARCH

END-CALL

END-MULTIPLY

END-START

END-COMPUTEEND-PERFORM

END-STRING

END-DELETE

END-READ

END-DIVIDE

END-UNSTRING

END-EVALUATE

END-REWRITE

END-WRITE

END-IF

An explicit Scope Terminator is paired with the unpaired occurrence of

the verb. An implicit Scope Terminator is a separator period.

Notes:

Example:

PERFORM PARA-1 UNTIL A > 10STATEMENT1STATEMENT2---------------------------------------

END-PERFORM.

Period (.) should not encounter in between PERFORM and END-PERFORM.Since it indicates end of the PERFORM statement, then compiler error will raise.

DISPLAY Verb

The function of the DISPLAY statement is to display low-volume results

on the operators console or some other hardware device.


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Syntax:

>>____DISPLAY_____ __identifier-1___ __ |

_____________________________________________>

| _ literal-1______|

E.g:

PROCEDURE DIVISION.

DISP-PARA.

DISPLAY SRCH-ARG NOT IN TABLE..

----------------------------------

-------------------------------

DISPLAY HELLO HOW ARE YOU.

Notes:

The DISPLAY statement transfers the contents of each operand to the outputdevice. The contents are displayed on the output device in the order, left to right,in which the operands are listed.

WITH NO ADVANCING when specified, the positioning of the output devicewill not be changed in any way following the display of the last operand.

ACCEPT Verb

Format 1 transfers data from an input/output device into identifier-1.

When the FROM phrase is omitted, the system input device isassumed.


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Format 1 is useful for exceptional situations in a program whenoperator intervention (to supply a given message, code, or

exception indicator) is required.

Format 1 :

>>__ACCEPT______identifier-1__________________________________ ______________>>___ADD_______ identifier-1_ _|__ To _____identifier-2__ ________

____________ __|_________>

|_literal-1___| |_ROUNDED _|

>___ ____________________________________________________

___________________________>

|_ ____ __SIZE ERROR imperative-statement-1______|

>___ _____________________________________________________

___________________________>

|_ NOT___ ______ ___SIZE ERROR__imperative statement_2_|

>___ _______ _________________________________________________>

|_ END-ADD_|

In Format 1, all identifiers or literals preceding the key word TO be

added together and this sum is stored in a temporary data item. This|temporary data item is then added to each successive occurrence of

identifier-2, in the left-to-right order in which identifier-2 is specified.

Identifier must name an elementary numeric item. Literal must be a

numeric. The ADD statement sums two or more numeric operands and

stores the result.

Example:ADD A TO B.

ADD 112 TO B.

ADD A TO B ON SIZE ERROR GO TO ERR-PARA.


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ADD Verb (Continue.)

The operands preceding the GIVING are added together and thesum replaces the value of each identifier-3


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Identifiers must be elementary numeric items, except whenfollowing GIVING then they may also be numeric edited.

Format 2:

>>___ADD_______ identifier-1_ _|__ ___ _ ____ _ __ _ identifier-2____________________________>

|_literal-1___| |_TO_| |_literal-2______|

>___ GIVING ___________identifier-3__ ______________ _|

___________________________________ >

|_ ROUNDED__|

>___ _____________________________________________________

____________________________ >

|_ _________ ___SIZE ERROR__imperative statement_1_|

>___ _____________________________________________________

___________________________ >

|_ NOT___ ______ _SIZE ERROR__imperative statement_2_|

|_ ON_|

>___ _______ _________________________________________________ >

|_ END-ADD_|

In Format 2, the values of the operands preceding the word GIVING

are added together, and the sum is stored as the new value of each data

item referenced by identifier-3.

Identifier must name an elementary numeric item, except when

following the word GIVING. Each identifier following the word

GIVING must name an elementary numeric or numeric-edited item

Literal must be a numeric.


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Example:ADD A TO B GIVING C

ADD CORRESPONDING Statement

Elementary data items within identifer-1 are added to, and storedin the corresponding elementary data items with identifer-2.

ADD CORRESPONDING identifiers must be group items


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Format:

>>___ADD_______ CORRESPONDING_ ___identifier-1___ TO___ identifier-

2____________________>

|_CORR__________|

>___ ______________ __ ______________________________________________

________________ >

|_ ROUNDED__| | _ ___ __SIZE ERROR____ imperative-statement-1_|

|_ ON_ |

>___ _____________________________________________________

___________________________ >

|_NOT___ ______ __SIZE ERROR__imperative statement_1_|

|_ON___|

>___ _____________________________________________________

___________________________ >|_ NOT___ ______ _SIZE ERROR__imperative statement_2_|

|_ ON_|

>___ _______ _________________________________________________ >

|_ END-ADD_|

In Format 3, elementary data items within identifier-1 are added to and

stored in the corresponding elementary items within identifier-2.

Identifier must name a group item. Literal must be a numeric.

Notes:

ON SIZE ERROR Phrase

If the value of an arithmetic evaluation exceeds the largest valuethat can be contained in a result, then a size error condition exists.

The SIZE ERROR condition applies to final results, notintermediate calculations


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If ON SIZE ERROR phrase is not specified, then truncation of theresults will occur.

If ON SIZE ERROR phrase is specified, the imperative statement(in ON SIZE ERROR) is taken, following which control is

transferred to the end of the arithmetic statement.

For ADD CORRESPONDING or SUBTRACTCORRESPONDING, the ON SIZE ERROR imperative is not

taken until all individual additions or subtractions have been

completed.

A size error condition can occur in three different ways:

When the absolute value of the result of an arithmetic evaluation,after decimal point alignment, exceeds the largest value that can be

contained in the result field

When division by zero occurs In an exponential expression, as indicated in the following table:

Sizeerror Actiontakenwhen aSIZEERRORclause is present

ActiontakenwhenaSIZEERROR clause is not present

Zero raised to zero

power

The SIZE ERROR

imperative is executed.

The value returned is 1, and

message is issued.Zero raised to anegative number

The SIZE ERRORimperative is executed.

Program is terminatedabnormally.

A negative numberraised to a fractional

power

The SIZE ERROR imperativeis executed

The absolute value of the base iused, and a message is issued


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The size error condition applies only to final results, not to any

intermediate results.

NUMERIC Data

Types of numeric items are:

Binary Packed decimal. (Internal decimal) Floating point representation.


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The PICTURE character-string can contain only the symbols 9, P,S and V

The number of digit positions must range from 1 through 18,inclusive

If unsigned, the contents of the item in standard data format mustcontain a combination of the Arabic numerals 0-9. If signed, it may

also contain a +, - or other representation of the operation sign

Notes:

A VALUE clause can specify a figurative constant ZERO.

SUBTRACT Verb

Format 1:

>>___SUBTRACT_______ identifier-1_ _|__

FROM_________________________________________>|_literal-1___|

> ______identifier-2__ _______________

_|________________________________________________>

| _ ROUNDED ____|


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>___ ____________________________________________________

___________________________>

|_ ____ __SIZE ERROR imperative-statement-1______|

|_ON _|

>___ _____________________________________________________

___________________________>

|_ NOT___ ______ ___SIZE ERROR__imperative statement_2_|

>___ _______ _________________________________________________>

|_ END-SUBTRACT_|

All identifiers or literals preceding the key word FROM are added

together and this sum is subtracted from and stored immediately in

identifier-2. This process is repeated for each successive occurrence of

identifier-2, in the left-to-right order in which identifier-2 is specified.

Notes:

SUBTRACT Verb (Continue.)

Format 2:

>>___SUBTRACT_______ identifier-1_ _|__ FROM ___ _ identifier-2__

__________________________>|_literal-1___| |_literal-2______|


___________________________________ >

|_ ROUNDED__|


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>___ _____________________________________________________

____________________________ >

|_ _______ ___SIZE ERROR__imperative statement_1_|

|_ ON _|

>___ _____________________________________________________

____________________________ >|_ NOT___ ______ _SIZE ERROR__imperative statement_2_|

|_ ON_|

>___ _______ __________________________________________________ >

|_ END-SUBTRACT_|

All identifier or literals preceding the key word FROM are added

together and this sum is subtracted from identifier-2 or literals-2. The

result of the subtraction is stored as the new value of each data item

referenced by identifier-3.

Notes:

Example:

1. SUBTRACT A FROM B.The value of a subtracted from the value of B and then the resultant value will bestored in B.

2. SUBTRACT 9 FROM C.3. SUBTRACT C FROM 9. Is not valid because 9 is a Literal.

SUBTRACT CORRESPONDING Statement

Format:

>>___SUBTRACT_______ CORRESPONDING_ ___identifier-1___

FROM________________________>

|_CORR__________|

>___ identfier-2____ __ ___________

_____________________________________________________ >

|_ ROUNDED__|

>___ _____________________________________________________

____________________________ >

|____ ______ __SIZE ERROR__imperative statement_1_|


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|_ON___|

>___ _____________________________________________________

____________________________ >


|_ ON__|

>___ _______ __________________________________________________ >

|_ END-SUBTRACT_|

Elementary data items within identifier-1 are subtracted from, and the

results are stored in, the corresponding elementary data items within

identifier-2.

Notes:

MULTIPLY Verb

Format 1:

>>___MULTIPLY_______ identifier-1___ ___BY____identifier-2___

__________________| __________>

|_ literal-1________|

>___ _____________________________________________________

____________________________ >|____ ______ __SIZE ERROR__imperative statement_1_|

|_ON___|

>___ _____________________________________________________

____________________________ >


|_ ON__|

>___ _______ _________________________________________________ >


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|_ END-MULTIPLY_|

In Format 1, the value of identifier-1 or literal-1 is multiplied by the value of

identifier-2; the product is then placed in identifier-2. For each successive

occurrence of identifier-2, the multiplication takes place in the left-to-right

order in which identifier-2 is specified.

Notes:

The MULTIPLY statement multiplies numeric items and sets the values of dataitems equal to the results.

MULTIPLY Verb (continue..)

Format 2:

>>___MULTIPLY_______ identifier-1_ _|__ BY_______ _ identifier-2__

__________________________>

|_literal-1___| |_literal-2______|


___________________________________ >

|_ ROUNDED__|

>___ _____________________________________________________

____________________________ >


|_ ON _|


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>___ _____________________________________________________

____________________________>


|_ ON_|

>___ _______ _________________________________________________ >

|_ END-MULTIPLY_|

In Format 2, the value of identifier-1 or literal-1 is multiplied by the

value of identifier-2 or literal-2. The product is then stored in the data

item(s) referenced by identifier-3.

Notes:

DIVIDE Verb

Format 1:

>>___DIVIDE_____ _____ identifier-1_ _|__ INTO__________identifier-2_____________ __ |____>

|_literal-1___||_ROUNDED _|

>___ ________________________________________________________________________________>

|_ ____ __SIZE ERROR imperative-statement-1____________|

|_ON _|>___ _____________________________________________________

____________________________>|_ NOT___ ______ ___SIZE ERROR__imperative statement_2_|

|_ON __|>___ _______ __________________________________________________>

|_ END-DIVIDE_|


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In Format 1, the value of identifier-1 or literal is divided into the value

of identifier-2, and the quotient is then stored in identifier-2. For each

successive occurrence of identifier-2, the division takes place in the left-

to-right order in which identifier-2 is specified.

Notes:

The DIVIDE statement divides one numeric data item into or by other(s) and setsthe values of data items equal to the quotient and remainder

DIVIDE Verb (Continue)

Format 2:

>>___DIVIDE_______ identifier-1_ _|__ INTO_______ _ identifier-2__

___________________________>

|_literal-1___| |_literal-2______|


___________________________________ >

|_ ROUNDED__|

>___ _____________________________________________________

____________________________ >|_ _______ ___SIZE ERROR__imperative statement_1_|

|_ ON _|

>___ _____________________________________________________

____________________________>


|_ ON_|


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>___ _______ _________________________________________________ >

|_ END-DIVIDE_|

In Format 2, the value of identifier-1 or literal-1 is divided into or by the

value of identifier-2 or literal-2. The value of the result is stored in each

data item referenced by identifier-3.

Notes:

COMPUTE Verb

Format:

>>___COMPUTE_______ identifier-1_ ____________ _|____ _ =______

__________________________>|_ ROUNDED _| |_ EQUAL_|

>___ arithmetic

expression_______________________________________________________________

_ >

____________________________ >


|_ ON _|

>___ _________________________________________________________________________________ >


|_ ON_|

>___ _______ __________________________________________________ >

|_ END-COMPUTE_|


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The arithmetic expression is calculated and replaces the value for each

identifier-1 item. Valid operators allowed in the expression are:

+ addition - subtraction

* multiplication / division

** exponentiation

Notes:

The COMPUTE statement assigns the value of an arithmetic expression to one ormore data items.

With the COMPUTE statement, arithmetic operations can be combined withoutthe restrictions on receiving data items imposed by the rules for the ADD,

SUBTRACT, MULTIPLY, and DIVIDE statements.

Identifier-1

Must name elementary numeric item(s) or elementary numeric-edited item(s). Canname an elementary floating-point data item. The word EQUAL can be used in

place of =.

An arithmetic expression ca consists of any of the following:

1. An identifier described as a numeric elementary item2. A numeric literal3. The figurative constant ZERO4. Identifiers are literals, as defined in terms 1,2, and 3, separated by

arithmetic operators5. Two arithmetic expressions, as defined in items 1,2,3, and/or 4, separated

by an arithmetic operator6. An arithmetic expression, as defined in items 1,2,3,4 and/or 5, enclosed in

parentheses.

When the COMPUTE statement is executed, the value of the arithmetic expressionis calculated, and this value is stored as the new value of each data item referenced

by identifier-1.


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PERFORM Statement

PERFORM Paragraph-name/Section-header

Transfer the control to the specified paragraph or section and expects

the control back after executing the paragraph.

PERFORM Para-name-1 [ THROUGH (or) THRU Para-name-n]

Notes:


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PERFORM types

PERFORM Para-name PERFORM Para-name N TIMES PERFORM Para-name VARYING K FROM M BY N UNTIL CONDITION

K>20 PERFORM Para-name VARYING K FROM M BY N UNTIL CONDITION

K>20 AFTER VARYING.

PERFORM THROUGH

PROCEDURE DIVISION.

100-MAIN-PARA.

PERFORM 200-PARA THRU 500-PARA.

STOP RUN.

200-PARA.

* Statements.

400-PARA.

* Statements

500-PARA.

* Statements

300-PARA.

* Statement - Not executed

All the paragraphs between 200-PARA and 500-PARA are executed.

Notes:


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70

PERFORMN times

PERFORM PARA-NAME-1[THROUGH (or) THRU PARA-NAME-N]

N TIMES.

EX:

PERFORM PARA-1000 15 TIMES.

PERFORM PARA-1000 THRU PARA-4000 15 TIMES.

PARA-1000.

ADD A TO B.

------------------------

-------------------------

PARA-2000.

SUBTRACT A FROM B.

-------------------------------

-------------------------------

PARA-4000.

MULTIPLY A BY B.

----------------------------

Notes:


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PERFORMVARYING

PERFORM PARA-NAME-1 [THRU (or) THROUGH PARA-NAME-N]VARYING { identifier- 1 } {identifier-2 }

{Index-name-1} FROM {index-name-2}

{ Literal-1 }

BY {identifier-3 } UNTIL Condition

{Literal-2 }

EX:

PERFORM PARA-2000 THRU PARA-5000 VARYING A FROMM BY N UNTIL A > Y

PERFORM para-1 Varying K FROM 10 BY 5 UNTIL K>100

Notes:

Example 2 says:

Sets the value of K to 10 initiallyExecute para-1


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Check the condition K > 100If condition is true, transfer the control to next lineIf condition is false, increment K by 5Execute para-1 againCheck the condition K > 100Repeat steps from 2 through 7 until Condition K > 100 becomes true

Flow Chart for PERFORM .. VARYING

False

True

Enter

Set identifier 1to initial value

Condition

Execute range

Add increment to -identifier.

Exit

False

True


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PERFORM with the VARYING-AFTER Option

PERFORM PARA-NAME-1 [THRU (or) THROUGH PARA-NAME-N]VARYING { identifier- 1 } {identifier-2 }

{Index-name-1} FROM {index-name-2}

{Literal-1 }

BY {identifier-3 } UNTIL Condition-1{Literal-2 }

AFTER { identifier- 4 } {identifier-5 }{ Index-name-3} FROM {index-name-4}

{ Literal-3 }

BY {identifier-6} UNTIL Condition-2{Literal-4 }

AFTER { identifier- 7 } {identifier-8 }{Index-name-5} FROM {index-name-6}

{ Literal-5 }

BY {identifier-9 } UNTIL Condition-3{Literal-6 }

This form is used when a nested repetition of the range is required while varyingmore than one identifier.


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74

For example:PERFORM RANGE-TO-BE-EXECUTED

VARYING I FROM 1 BY 1 UNTIL I > 50AFTER J FROM 1 BY 1 UNTIL J > 10.

The range RANGE-TO-BE-EXECUTED will be performed 500 times,.

In-Line PERFORM

The in-line PERFORM will be coded using END-PERFORM.

Named Paragraph

PERFORM MOVEIT

VARYING X FROM 1 BY 1 UNTIL X = 5.. . .

MOVEIT.MOVE DATA-FLD (X) TO PRINT (X).

In-line PERFORM

PERFORM VARYING X FROM 1 BY 1 UNTIL X = 5.MOVE DATA-FLD (X) TO PRINT (X).

END-PERFORM.

Notes:

An In-line PERFORM requires the END-PERFORM terminator. Conversely theEND-PERFORM phrase must not be specified when the statement is PERFORM

procedure name.


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75

IN-LINE PERFORM Considerations

DO not use for procedures executed from several places/ Use for procedures referenced only once. Consider not using if readability is affected , such as multiple-page

PERFORM,

No periods may appear within the in-line PERFORM. Delimited by END-PERFORM. END-PERFORM cannot be used at end of an out-of-line PERFORM. The OPTIMIZE compile option may move the PERFORM in-line in

the object code at the compile time.


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76

IF... ELSE Statement

The IF statement evaluates a condition and provides for alternative actions in

the object program, depending on the evaluation.

Format :

>>_______IF_____Condition-1____ __________ _____ ___statement-1___|__ ____________________>

|_THEN_____| |_NEXT SENTENCE _|>___ ____________________________ ____ ________________

______________________________>

|


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Compound Conditionals

Conditional expressions can be compound using the AND and OR

logical operators

Conditional conditions can also use parentheses to group conditions.

IF ITEM-1 = DOMESTIC-ITEM-NOAND ITEM-2 = OVERSEAS-ITEM-NO

ORITEM-1 = OVERSEAS-ITEM-NO

AND ITEM-2 = DOMESTIC-ITEM-NOSET MIXED-SHIPMENT-FLAG TO TRUE

END-IF

.SEARCH TABLEPAIR VARYING NDXWHEN ITEM-1(NDX) = FROM-CITY AND ITEM-2(NDX) = TO-CITY

MOVE WHEN ITEM-2(NDX) = FROM-CITY AND ITEM-1(NDX) = TO-CITY

MOVE ..END-SEARCH

Notes:

Relational Expressions


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78

Relational tests (comparisons) can be express as:

IS LESS THAN IS EQUAL TO =

IS NOT EQUAL TO NOT =

IS GREATER THAN OR EQUAL TO >=

IS LESS THAN OR EQUAL TO


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79

IF C = DNEXT SENTENCEELSE

MOVE MESSAGE-1 TO RPT-MESSAGE-1END-IF

ADD C TO TOTAL

DISPLAY TOTALIF E = FMOVE MESSAGE-4 TO RPT-MESSAGE-2

END-IFEND-IF.

Example 2 - CONTINUEIF A = B

IF C = DCONTINUE

ELSE

MOVE MESSAGE-1 TO RPT-MESSAGE-1END-IFADD C TO TOTALDISPLAY TOTALIF E = F

MOVE MESSAGE-4 TO RPT-MESSAGE-2END-IFEND-IF.

Notes:

EVALUATE Statement

EVALUATE is a great way to implement the case programming

construct

EVALUATE datanameWHEN value-1 .WHEN value-2 {THROUGH | THRU} value-3 .

WHEN NOT value-4


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Basic EVALUATE Example:

The scope of a WHEN clause is all statements UNTIL the next WHEN

clause, the END-EVALUATE, or a period

Notes:

The EVALUATE statement provides a shorthand notation for a series of nested IFstatements. It can evaluate multiple conditions. That is, the IF Statements can bemade up of compound conditions.

Examples:

Working-Storage for all Examples:

01 PLANET.05 PLANET-NUMBER PIC 9.05 PLANET-NAME PIC X(7).

Evaluate Example Number 1: (Evaluate a PIC 9 field)

EVALUATE datanameWHEN A Perform add-transWHEN D Perform delete-transWHEN UWHEN W Perform update-transWHEN OTHER Perform bad-trans

END-EVALUATE


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EVALUATEPLANET-NUMBERWHEN 1 MOVE "Mercury" TO PLANET-NAMEWHEN 2 MOVE "Venus " TO PLANET-NAMEWHEN 3 MOVE "Earth " TO PLANET-NAMEWHEN 4 MOVE "Mars " TO PLANET-NAMEWHEN 5 MOVE "Jupiter" TO PLANET-NAME

WHEN 6 MOVE "Saturn " TO PLANET-NAMEWHEN 7 MOVE "Uranus " TO PLANET-NAMEWHEN 8 MOVE "Neptune" TO PLANET-NAMEWHEN 9 MOVE "Pluto " TO PLANET-NAMEWHEN OTHER MOVE " " TO PLANET-NAME

END-EVALUATE.

Evaluate Example Number 2: (Evaluate a PIC X field)

EVALUATEPLANET-NAMEWHEN "Mercury" MOVE 1 TO PLANET-NUMBER

WHEN "Venus " MOVE 2 TO PLANET-NUMBERWHEN "Earth " MOVE 3 TO PLANET-NUMBERWHEN "Mars " MOVE 4 TO PLANET-NUMBERWHEN "Jupiter" MOVE 5 TO PLANET-NUMBERWHEN "Saturn " MOVE 6 TO PLANET-NUMBERWHEN "Uranus " MOVE 7 TO PLANET-NUMBERWHEN "Neptune" MOVE 8 TO PLANET-NUMBERWHEN "Pluto " MOVE 9 TO PLANET-NUMBERWHEN OTHER MOVE 0 TO PLANET-NUMBER

END-EVALUATE.

Evaluate Example Number 3:Let each of MONTH and NO-OF-Days be two-digited numeric integer fields. The values1,2,3, etc. for MONTH denote respectively, January, February, March etc. depending onthe value of MONTH , we wish to ove 30,31 or 28 to NO-OF-DAYS. For example , ifthe value of MONTH is 1, we shall move 31; if it is 2, we shall move 28 and so on. TheEVALUATE statement for the purpose is as follows:

EVALUATETRUEWHEN MONTH = 4 OR 6 OR 9 OR 11

MOVE 30 TO NO-OF-DAYSWHEN MONTH = 2

MOVE 28 TO NO-OF- DAYSWHEN OTHER MOVE 31 TO NO-OF-DAYSEND EVALUATE.

In this case, we have assumed that MONTH has a correct value.

Evaluate Example Number 4:

Suppose MARKS contains the marks obtained by a student. GRADE is an one- characteralphanumeric field. We wish to calculate GRADE according to the following rules


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MARKS GRADE

80 100 A60 - 79 B45 - 59 C30 - 44 D

0 - 29 EThe EVALUATE statement for the purpose is shown below.EVALUATE MARKS

WHEN 80 THRU 100 MOVE A TO GRADEWHEN 60 THRU 79 MOVE B TO GRADEWHEN 45 THRU 59 MOVE C TO GRADEWHEN 30 THRU 44 MOVE D TO GRADEWHEN ZERO THRU 29 MOVE E TO GRADEWHEN OTHER MOVE W TO GRADE

END-EVALUATE.

The literal W is moved to GRADE in the case of wrong marks.

ILLUSTRATES CONDITION NAMES

DATA DIVISION.


77 MARTIAL-STATUS PIC 9.88 SINGLE VALUE 0.88 MARRIED VALUE 1.88 WIDOWED VALUE 2.88 DIVORCED VALUE 3.88 ONCE-MARRIED VALUES ARE 1, 2, 3.


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88 VALID-STATUS VALUES ARE 0 THRU 3.77 AMOUNT PIC 9 (4) VALUE 1000.

PROCEDURE DIVISION.

MAIN-PARA.DISPLAY Martial Status:DISPLAY 0- Single / 1- Married / 2- Widowed / 3- Divorced.ACCEPT MARTIAL-STATUS.IF NOT VALI-STATUS DISPLAY Error in Entry.IF SINGLE SUBTRACT 100 TO AMOUNT.IF MARRIED ADD 100 TO AMOUNT.IF WIDOWED ADD 200 TO AMOUNT.IF DIVORCED SUBTRACT 200 FROM AMOUNT.IF ONCE-MARRIED ADD 250 TO AMOUNT

DISPLAY AMOUNT.STOP RUN.

INITIALIZE Statement

The INITIALIZE statement sets selected categories of data fields topredetermined values. It is functionally equivalent to one or more MOVEstatements.

When the REPLACING phrase is not used:

SPACE is the implied sending field for alphabetic alphanumeric,alphanumeric-edited, and DBCS items. ZERO is the implied sending fieldfor numeric and numeric-edited items.

>>___INITIALIZE____identifier-1_________________________________________________________________>

_______>>__SET____condition-name-1_|_ TOTRUE_________________________>>____READ__file-name-1___ _________________ __ __________ ___________________>|_ NEXT __________| |_RECORD__||_ (1)||_ PREVIOUS______|

>_____ _______________________ ______________________________________________>|____ INTO___identifier-1____|

>_____ ___________________________________ __________________________________>|_ ____ __END_imperative statement-1_|

|_ AT _|>_____ ____________________________________________ ____ __________ _______>>_____READ______file-name-1____ __________ ___ _______________ _____________>

>____ _____________________________ ________________________________________>|_KEY_____ ___ __data-name-1__|

|_TO_|

>_____ _______________________________________________ ______________________>|_INVALID_____ ______ ____imperative-statement-3__|

|_KEY __|

>____ ___________________________________________ ___ ____________ _______>>___START___file-name-1___________________________________________________________>

>__ _____________________________________________________________________ ________>|_KEY___ ______ ____ __EQUAL___ ___ ________________ _data-name-1____|

|__TO _| | |_ TO_| ||_ = ______________________________||_LESS__ _______ ________________|| |_THAN_| ||_GREATER__ ____ _____________|| |_THAN_| ||_NOT LESS___ _______ ___________|| |_THAN _| ||_NOT < ___________________________||_NOT GREATER__ _______ ________|| |_THAN_| |

|_NOT > ___________________________||_LESS_ ____ _ OR EQUAL_ __ _____|| |THAN| |_TO_| ||_GREATER__ ____ _OR EQUAL_ __ _|| |_THAN_| \TO||_>+_______________________________|

>__ _______________________________________ _____________________________________>|_INVALID___ _____ _imperative-statement-1_|

|_KEY_|>__ _______________________________________ ___________ ____________ _____________>

|_NOT INVALID___ _____ imperative-statement-1_| |_END-START_||_KEY_|

Notes:

The START statement provides a means of positioning within an indexed orrelative file for subsequent sequential record retrieval. When the STARTstatement is executed, the associated indexed or relative file must be open in eitherINPUT or I-O mode.

file-name-1

Must name a file with sequential or dynamic access. File-name-1 must be definedin an FD entry in the Data Division, and must not name a sort file.

END-START Phrase

This explicit scope terminator delimits the scope of the START statement. END-START converts a conditional START statement to an imperative statement sothat it can be nested in another conditional statement. END-START can also beused with an imperative START statement.


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WRITE Statement

The WRITE statement releases a logical record for an output orinput/output file.

When the WRITE statement is executed:- The associated sequential file must be open in OUTPUT or

EXTEND mode.- The associated indexed or relative file must be open in OUTPUT, I-

O, or EXTEND mode. Record-name must be defined in a Data Division FD entry. Record-

name can be qualified. It must not be associated with a sort or merge

file.

Notes:


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WRITE.FROM

PROCEDURE DIVISION.

WRITE File-rec FROM Identifier.

File-rec is record-name declared in FILE-SECTION. Identifier is a working-storage section variable The length of the identifier should be equal to the length of the

record.

Notes:

To Create a file, program can accept the data from the terminal into file record andwrite it.

If the data need to be processed, it can be accepted in a W-S identifier. Afterprocessing the data the above WRITE..FROM statement can be issued.

Each WRITE statement writes one record at a time.


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READ.INTO

PROCEDURE DIVISION.

READ FILE-name (INTOW-S-Rec) | (AT END Statement)

File name is defined in SELECT clause. W-S-Rec is working-Storage section identifier. INTO clause moves the file record to W-S-rec. AT END clause if used, indicates the next action after the last record

is read.

OPEN INPUT Mode

Notes:

READ statement on sequential files reads one record at a time and makes itavailable to program.

Reading begins from first record and if the READ statement is put in a loop. Thatis executing the statement repeatedly, then it is possible to read consecutiverecords.

Loop can be terminated before AT END condition is reached if required so by theprogram.

If the file is left open next time when the read statement executes, readingcontinuous from where it was stopped before the termination of loop.

If the file is closed then it is to be opened again before reading it.


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109

REWRITE & DELETE

REWRITE record-name (FROM identifier)

Updates an existing record from W-S identifier.

OPEN I-O File-name

DELETE record-name -----------------not allowed

Deleting of a record in sequential files not allowed.

Notes:

It is often required to change the existing data and the process is calledUPDATING.

COBOL provides REWRITES verb to modify an existing record.

For example, changing the address field of an employee requires reading ofemployee number. Every record to be updated needs to be read first. To searchthe record of an employee, whose employee number is known, the process is asfollows

Store the employee number in a variable Open the file Read first record Compare the variable with Emp-No field of the file If it matches update his address by REWRITE Else read next record his address by REWRITE Repeat the process until the require record is read.


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Appending to sequential files

Adding new records to the existing file.

OPEN EXTEND Mode

WRITE records.

When new records to be added to file open the file in EXTEND modeEXTEND mode causes the pointer to move to the end of the file.

Notes:


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CLOSE Statement

Format :

CLOSE File-name-1, [File-name-2 .]

CLOSE Statement Releases the Resourcces which are assigned to that file.

Cannot Close the file which is not opened.

After performing the operations on the file (I,e no longer usedin a program) needs to beclosed but not necessary.

If the FILE STATUS clause is specified in the FILE-CONTROL entry, the associatedstatus key is updated when the CLOSE statement is executed.

If the file is in an open status and the execution of a CLOSE statement is unsuccessful,the EXCEPTION/ERROR procedure (if specified) for this file is executed.

Notes:


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Sequential Files

ENVIRONMENT DIVISION.INPUT-OUTPUT SECTION.

FILE-CONTROLSELECT file-name ASSIGN TO DEVICE-NAMEORGANIZATION IS SEQUENTIAL.ACCESS MODE IS SEQUENTIAL. AreaFILE STATUS IS data-name. B

Notes:

All the files used in the program should have an entry in FILE CONTROLparagraph.

For each file used, there should be one SELECT..ASSIGN clause.

The file-name is select clause is user defined word and can be used throughout theprogram wherever required.

ASSIGN clause specifies the device on which file stored.


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