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Chapter 3

To familiarize you with Ways in which data is organized in COBOL Rules for forming data-names Defining input and output files in DATA

DIVISION Defining storage for work fields and

constants Forming Data-Names The FILE SECTION of the DATA DIVISION Types of Data WORKING-STORAGE SECTION of the DATA

DIVISION

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Fully Interactive Programs◦ Use ACCEPT to get input from keyboard◦ Use DISPLAY to display output on screen

Full Batch Programs◦ Get input from files on disk◦ Direct output to files on disk

Hybrid Programs◦ Use combination of interactive and batch input

and output methods

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Field - group of characters forming a meaningful unit or basic fact◦ Characters in a name or digits in an amount

Records - group of related fields◦ All fields related to customer

File - group of related records◦ Customer file made up of customer records

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1. Date-Of-Birth2. Amount$Out3. Section4. -First-Name5. 98-66. Time out

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1.Use meaningful data-names that describe contents of field• Amount-Due-In instead of A1

2.Use prefixes or suffixes in data-names when appropriate• -IN and -OUT for fields (Emp-Salary-IN and Emp-

Salary-OUT)• -FILE and -RECORD for file and record names

(Emp-File and Emp-Record)

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Defines, describes storage for all data Two main sections

◦ FILE SECTION Defines all input and output files, records, fields• Required for any program that uses files, typically

batch programs◦ WORKING-STORAGE SECTION

Defines constants, end-of-file indicators and work areas

Defines fields not part of input or output files

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• Input files• Master files• Transaction files -> updates

• Output files• New Master files -> mix the two to get• Report files

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• Each file described with an FD (File Descriptor) sentence

• One FD for each SELECT statement in ENVIRONMENT DIVISION

• FD followed by• File-name• Optional clauses to describe file and format of its

records

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FD file-name RECORD IS OMITTED LABEL RECORDS ARE STANDARD

RECORD CONTAINS integer-1 CHARACTERS BLOCK CONTAINS integer-2 RECORDS .

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LABEL RECORDS clause◦ Used if labels stored in file (OS will handle this for

us, so we won’t use this clause) BLOCKS CONTAINS clause

◦ Indicates blocking factor for disk files (We won’t be using this clause) Has to do with disks that store data relative to blocks.

Just in case you see it later.

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Indicates size of each record Optional but recommended since it provides

check on record size Given this FD FD Sales-File Record Contains 75 Characters.

If PICTURE clauses mistakenly add up to 76, compiler will report a syntax error

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• Each FD (File Descriptor) followed by record description entries for the file

• Data grouped in COBOL by levels• Record-name defined at the 01 level• Considered highest level of data

• Fields within a record defined at subordinate level with level numbers from 02 to 49

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01 Employee-Rec-In. 05 Name-In … 05 Annual-Salary-In … 05 Job-Description-In …

• Fields at 05 level subordinate to 01 level entry

• All fields at same level (05), independent or not subordinate to each other

• Leave room in numbering in case you need to add in between.

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• REVIEW:• SELECT names file, assigns it to hardware device• FD describes file• 01 names record• 02-49 describes fields within record

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Items defined with a level number are one of two types◦ Elementary item - field that is not further

subdivided Must include a PICTURE clause

◦ Group item - field that is further subdivided Has no PICTURE clause

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01 Employee-Rec-In. 05 Name-In …

10 First-Name-In (Picture clause)

10 Last-Name-In (Picture clause) 05 Annual-Salary-In (Picture clause)

• Name-In is group item since it is subdivided into first and last name

• Employee-Rec-In also group item• First-Name-In is elementary item since it is

not further subdivided

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01 Employee-Rec-In. 05 Name-In …

10 First-Name-In (Picture clause) 12 Last-Name-In (Picture clause)

05 Annual-Salary-In (Picture clause)

• Last-Name-In level number is invalid since it is not subordinate to First-Name-In• Makes no sense because First-Name-In wouldn’t

have a PIC clause and same indentation• Both first and last name are at same level and

should have same level number

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• Specify type of data stored in field• Indicate size of field

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• Alphabetic• Only letters or blanks • For name, item description, etc.

• Alphanumeric• Any character - letters, digits, special

characters• For an address like 123 N. Main St.

• Numeric• Only digits• For fields used in arithmetic operations

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• A for alphabetic• X for alphanumeric• 9 for numeric

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Denote size of field by: Number of A’s, X’s or 9’s used in PICTURE

01 Cust-Rec-In.05 Cust-ID-In Picture XXXX.05 Amt-In Picture 99999.

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My also denote size of field by: A, X or 9 followed by number in parentheses

01 Cust-Rec-In.05 Cust-ID-In Picture X(4).05 Amt-In Picture 9(5).

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Must account for all positions defined in record layout

Must describe fields in order they appear in record

Field names should be unique For fields not used by program

◦ Data-name may be left blank (preferable)◦ May use reserved word FILLER as data-name◦ Positions must still be defined using PIC clause◦ Common for printing/display

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For fields used in arithmetic operations Symbol V used in PIC clause to denote

location of implied decimal point Decimal point itself not stored as part of

number To store value 26.79 in field AMT-IN, code

entry as

05 Amt-In Pic 99V99.

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• Entries in DATA DIVISION reserve storage for data

• Entries in FILE SECTION reserve storage for data from records in input/output files

• WORKING-STORAGE SECTION reserves storage for keyed input/output

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• Data with a fixed value• Value that does not depend on input• Examples:• Fixed tax rate of .05• Message “INVALID” displayed when a value is in

error• .05 and “INVALID” are constant values

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• Numeric literal• Examples: .05 5280 199.99• Constant used for arithmetic operations

• Nonnumeric (alphanumeric) literal• Examples: “INVALID” “Enter your name”

• Figurative constant• SPACES ZEROS• Reserved word for commonly used values

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• Must be enclosed in quotation marks• From 1 to 160 characters, including space• Any character in COBOL character set

except quotation mark

Valid Nonnumeric Literals

'123 Main St.' '$14.99' '12,342' 'Enter a value from 1 to 10'

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Only characters within quotes are moved or displayed

May contain all numbers ('125') but not same as numeric literal (125)◦ Cannot be used in arithmetic operations◦ Cannot be moved to field with PIC of 9’s

Are not data-names◦ 'Amount-In' not same as field defined in DATA

DIVISION called Amount-In

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ZERO, ZEROS or ZEROES means all zeros

Move Zeros To Total-Out

Fills each position in Total-Out with a zero May be used with both numeric and

alphanumeric fields

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Example

SPACE or SPACES means all spaces or blanks

Move Spaces To Code-Out

Fills each position in Code-Out with a space or blank

Use only with alphanumeric fields since blank is invalid numeric character

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Example

Follows FILE SECTION Begins with heading on line by itself Starts in Area A, ends with period All items must be defined at 01 level or in

entries subordinate to 01 level entry

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Rules for user-defined data-names apply Elementary items:

◦ Must include PICTURE clause◦ May be assigned initial value with VALUE clause

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To define fields used for Keyed input and displayed output Intermediate arithmetic results Counters and totals End-Of-File Indicators

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To define initial value for field If omitted, field’s value undefined when

program begins execution May be used only in WORKING-STORAGE

SECTION

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VALUE clause used in DATA DIVISION◦ Gives initial value before execution begins

MOVE used in PROCEDURE DIVISION◦ Assigns value to field after program begins

MOVE may change initial value of field

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Contains literal or figurative constant Data type must match PICTURE

Numeric literals or ZEROS used with PIC 9 fields 01 WS-Tax-Rate Pic V99 Value .06. 01 WS-Total Pic 999 Value Zeros.

Nonnumeric literals, ZEROS or SPACES used with PIC X fields 01 WS-EOF Pic X(3) Value ‘YES’. 01 WS-Descrip Pic X(8) Value Spaces.

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Define a literal of .28 (28%) for a tax rate

Method 1 - code as literal in PROCEDURE DIVISION

Multiply .28 by WS-Salary Giving WS-Tax

Method 2 - store in data item in WORKING-STORAGE SECTION 01 WS-Rate Pic V99 Value .28.

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Method 2 - use data-name in place of literal in PROCEDURE DIVISION Multiply WS-Rate by WS-Salary Giving WS-Tax◦ Preferable for literals used more than once ◦ Reduces likelihood of error since literal value

entered one time◦ Allows meaningful name to be associated with

number

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Nonnumeric literals may be up to 160 characters

Long literals may not fit on one typed line Subdividing long literals into separate fields

is recommended You may need this when making a long

sentence.

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Separate this report title into two fields "Transaction Report for XYZ Corporation"

01 Report-Title. 05 Pic X(18) Value 'Transaction Report'. 05 Pic X(20) Value ' for XYZ Corporation'.

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Example

Long literals may be continued from one line to next, although this is not recommended

Rules for continuation of literals from one line to next ◦ Begin literal with quotation mark.◦ Continue literal to position 72. Do not end with

quotation mark.◦ Place hyphen on next line in position 7.◦ Continue literal with quotation mark starting

anywhere in Area B.◦ End literal with quotation mark.◦ Example p. 92

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1. LABEL RECORDS clause will be phased out entirely

2. VALUE clause will be allowed in FILE SECTION

3. Way to continue nonnumeric literals will change

4. Margins A and B rules will be guidelines rather than requirements

5. Commas and dollar signs will be permissible in numeric literals

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Data organized into files, records and fields Variable data changes with each run

depending on input values Constant or literal data defined within

program, not entered as input

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FILE SECTION includes FD entry for each file used by program

Record names coded at 01 level Field names coded at 02-49 level Fields must be defined in order they appear

in record

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Group items are further subdivided Elementary items are not subdivided Elementary items have PICTURE clause Codes X, A, 9, V used to describe data

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WORKING-STORAGE SECTION used for storing◦ Intermediate results, counters◦ End-of-file indicators◦ Interactive data accepted as input or displayed

VALUE clauses may be used in this section to initialize fields

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