lecture 2 1

ENVIRONMENT DIVISION defines files external to the program and devices. contains two sections:

1.CONFIGURATION SECTION. identifies computers for compiling and executing the program

SOURCE-COMPUTER. system-name. the computer that will be used for compiling the program

OBJECT-COMPUTER. system-name. the computer that will be used for executing or running the program

2. INPUT-OUTPUT SECTION. associates files in a COBOL program with files known to the OS

lecture 2 2

INPUT-OUTPUT SECTIONsupplies information concerning the input and

output devices used in the program

[INPUT-OUTPUT SECTION. FILE-CONTROL.

SELECT file-name ASSIGN TO implementor-name.]

FILE-CONTROL paragraphSELECT statements start in Area B followed by a period. file-name = name used in program. implementor-name = device on which file resides (i.e., file

path and name on disk in our case)varies from compiler to compiler

lecture 2 3

DATA DIVISION

Data items that appear in the program

DATA DIVISION.

[FILE SECTION.

[FD file-description-entry record-description-entry]

[WORKING STORAGE SECTION.

[record-description-entry . . .]]

lecture 2 4

DATA DIVISION

FILE SECTIONDefine an FD for every file

I.e., for every SELECT statement in the ENVIRONMENT DIVISION.

File type (input or output file information)The “physical characteristics” of these files must be defined

exactly WORKING-STORAGE SECTION (note the hyphen)

Reserves memory for non-I/O fields, e.g. variables and constants

Defines output lines (Printing reports, results, etc.)

lecture 2 5

FD (File Description) statement

FD file-name

[BLOCK CONTAINS integer-1 RECORDS]

[RECORD CONTAINS integer-2 CHARACTERS]

BLOCK CONTAINS (block description) statement (optional)RECORD CONTAINS (record description) statement (optional)

FILE SECTION

lecture 2 6

BLOCK CONTAINSSpecify blocking factor (# records per disk sector)Higher the factor fewer physical operationsToo low-level for us. OS does it for us.Optional.

RECORD CONTAINS Indicates the number of characters in a record The compiler verifies the sum of individual data item sizes against

the declared valueOptional.

FILE SECTION

lecture 2 7

RECORD DESCRIPTION

FD is followed by an associated record description :Size and type of each field within a recordOrder in which the fields appearRelationship of the fields to one another

Done through a combination of:PICTURE CLAUSESLEVEL NUMBERS

lecture 2 8

Picture Clauses Describe the type and size of a field Only three data types:

• Alphanumeric (PIC X)• Numeric (PIC 9)• Alphabetic (PIC A)

Format size is indicated by the number of times 9, X, or A appear XXXX is the same as X(4)

Can use PICTURE IS, PICTURE, PIC IS, PIC S denotes sign and appears at the beginning of PIC Assumed decimal point

– Use of a V, PIC 9V99 can hold 1.23

lecture 2 9

INCOMING RECORD DATA DIVISION RECORDDESCRIPTION

VALUES

v v v

9 87|65 4|3 | 210

01 INCOMING-DATA-RECORD. 05 STUDENT-NAME PIC 9V99. 05 STUDENT-NAME PIC 99V9. 05 STUDENT-NAME PIC 9. 05 STUDENT-NAME PIC V999.

9.87 65.4. 3 .210

Assumed Decimal Point

lecture 2 10

VALUE Clause

Initialize contents of a field with literals.

Literals Numeric : VALUE 3.00Non-numeric : VALUE ‘ENGINEERING’Figurative constants : VALUE SPACES

SPACE or SPACES, ZERO or ZEROS, QUOTE or QUOTES, ALL literal

lecture 2 11

Level numbersLEVEL Numbers express DATA hierarchy

• Describe the relationship between the fields in the record

• Order in which the fields appear matter

• Valid levels numbers between 01 to 49

• 01 level is the record-name; highest level of data (Starts in Area A)

• Items : 02 - 49 (Start in Area B)– Group - can be further divided, cannot have PIC claus

– Elementary - cannot be further divided, must have PIC clause

• Levels with the same number are independent items

• Lower levels of data have higher level #’s

• Indentation is not required, but good for readability

• Group item names end with a period

lecture 2 12

STUDENT-EXAM-RECORD

STUDENT-NAME EXAM-SCORESSS-NUM

LASTNAME

FIRSTNAME

INIT

MATH ENGLISH

ALG GEO READ VOC LIT

1 15 16 30 31 32 40 41 45 46 50 51 55 56 60 61 65

ALPHANUMERIC NUMERIC

Student Exam Record

lecture 2 13

01 STUDENT-EXAM-RECORD. 05 STUDENT-NAME. 10 LAST-NAME PICTURE IS X(15). 10 FIRST-NAME PICTURE IS X(15). 10 MID-INITIAL PICTURE IS X. 05 SOC-SEC-NUM PICTURE IS 9(9). 05 EXAM-SCORES. 10 MATH.

15 ALGEBRA PICTURE IS 9(5). 15 GEOMETRY PICTURE IS 9(5).

10 ENGLISH. 15 READING PICTURE IS 9(5). 15 VOCABULARY PICTURE IS 9(5). 15 LITERATURE PICTURE IS 9(5).

01 STUDENT-EXAM-RECORD. 04 STUDENT-NAME. 08 LAST-NAME PIC X(15). 08 FIRST-NAME PIC X(15). 08 MID-INITIAL PIC X. 04 SOC-SEC-NUM PIC 9(9). 04 EXAM-SCORES. 08 MATH.

12 ALGEBRA PIC 99999. 12 GEOMETRY PIC 99999..

08 ENGLISH. 12 READING PIC 99999. 12 VOCABULARY PIC 99999. 12 LITERATURE PIC 99999.

(a) Initial Coding

(b) Alternative Specification

Level Numbers and PICTURE Clauses

lecture 2 14

WORKING-STORAGE SECTIONDefines data names not referenced in the FILE SECTION.Stores results of calculations, flags, switch control, constantsUsed to define print lines (headings and details) Intermediate data storage

FILLER (reserved word) Defines a field not referenced elsewhere in the program Typically holds spaces or constants The word can be omitted (is optional) Can be used to denote format of a print line

WORKING-STORAGE SECTION.

01 HEADING LINE.

05 FILLER PIC X(10) VALUE SPACES.

05 PIC X(12) VALUE ‘STUDENT NAME’.

05 PIC X(110) VALUE SPACES.

lecture 2 15

COUNTERS and ACCUMULATORS

Counters and accumulators compute totals and/or averages. Defined in the DATA DIVISION and given initial values:

01 COUNTERS-AND-ACCUMULATORS.

05 EMPLOYEE-COUNT PIC 999 VALUE ZERO.

05 TOTAL-PAY-AMOUNT PIC 9(6)V99 VALUE ZERO.

COBOL has reserved words that you cannot use for variable names. You cannot use the word "COUNT" as a variable name, so use

something descriptive like "EMPLOYEE-COUNT".

lecture 2 16

(b) COBOL Entries

FD STUDENT-FILE RECORD CONTAINS 27 CHARACTERS.01 STUDENT-RECORD. 05 STU-NAME. 10 STU-LAST-NAME PIC X(15). 10 STU-INITIALS PIC XX. 05 STU-CREDITS PIC 9(2). 05 STU-UNION-MEMBER PIC X. 05 STU-SCHOLARSHIP PIC 9(4). 05 STU-GPA PIC 9V99.

STUDENT NAME

LASTGPA

INITIALSCREDITS UNION MEMBER

SCHOLARSHIP

(a) Program Specifications 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Development of a COBOL Program (File Section)

lecture 2 17(b) COBOL Entries

WORKING-STORAGE SECTION.01 CONSTANTS-AND-RATES. 05 PRICE-PER-CREDIT PIC 9(3) VALUE 200. 05 UNION-FEE PIC 9(2) VALUE 25. 05 ACTIVITY-FEES. 10 1ST-ACTIVITY-FEE PIC 99 VALUE 25. 10 1ST-CREDIT-LIMIT PIC 99 VALUE 6. 10 2ND-ACTIVITY-FEE PIC 99 VALUE 50. 10 2ND-CREDIT-LIMIT PIC 99 VALUE 12. 10 3RD-ACTIVITY-FEE PIC 99 VALUE 75. 05 MINIMUM-SCHOLARHSIP-GPA

PIC 9V9 VALUE 2.5.

(a) Excerpt from the Program Specifications

1. Calculate tuition due at the rate of $200 per credit.2. The union fee is $25.3. Compute the activity fee based on the number of credits taken; $25 for 6 credits or less, $50 for 7 to 12 credits, and $75 for more than 12 credits.4. Award a scholarship equal to the amount in the incoming record if, and only if, the GPA is greater than 2.5.

Development of a COBOL Program (Constants and Rates)

lecture 2 18

(a) Report Layout

1 2 3 4 5 6 7 8

1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6

1 S T U D E N T N A M E C R E D I T S T U I T I O N U N I O N F E E A C T F E E S C H O L A R S H I P T O T A L B I L L

2

3 X X X X X X X X X X X X X X X X X 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9

4 X X X X X X X X X X X X X X X X X 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9

5

6

Development of a COBOL Program (Print Lines)

lecture 2 19(b) COBOL Entries

01 HEADING-LINE. 05 FILLER PIC X VALUE SPACES. 05 FILLER PIC X(12) VALUE ‘STUDENT NAME’. 05 FILLER PIC X(10) VALUE SPACES. 05 FILLER PIC X(7) VALUE ‘CREDITS’. 05 FILLER PIC X(2) VALUE SPACES. 05 FILLER PIC X(7) VALUE ‘TUITION’. 05 FILLER PIC X(2) VALUE SPACES. 05 FILLER PIC X(9) VALUE ‘UNION FEE’. 05 FILLER PIC X(2) VALUE SPACES. 05 FILLER PIC X(7) VALUE ‘ACT FEE’. 05 FILLER PIC X(2) VALUE SPACES. 05 FILLER PIC X(11) VALUE ‘SCHOLARSHIP’. 05 FILLER PIC X(2) VALUE SPACES. 05 FILLER PIC X(10) VALUE ‘TOTAL BILL’.

05 FILLER PIC X(48) VALUE SPACES. 01 DETAIL-LINE. 05 FILLER PIC X VALUE SPACES. 05 DET-LAST-NAME PIC X(15). 05 FILLER PIC X(2) VALUE SPACES. 05 DET-INITIALS PIC X(2). 05 FILLER PIC X(5) VALUE SPACES. 05 DET-CREDITS PIC 9(2). 05 FILLER PIC X(2) VALUE SPACES. 05 DET-TUITION PIC 9(6). 05 FILLER PIC X(7) VALUE SPACES. 05 DET-UNION-FEE PIC 9(3). 05 FILLER PIC X(8) VALUE SPACES. 05 DET-SCHOLARSHIP PIC 9(5). 05 FILLER PIC X(6) VALUE SPACES. 05 DET-IND-BILL PIC 9(6).

05 FILLER PIC X(49) VALUE SPACES.

Development of a COBOL Program (Print Lines)