1. 3-1 Chapter 3

2. 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 3-2

3.  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 3-3

4.  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 3-4

5. 1. 1 to 30 characters 2. Letters, digits, hyphens (-) only 3. No embedded blanks 4. At least one alphabetic character 5. May not begin or end with hyphen 6. May not be COBOL reserved word 3-5

6. 1. Date-Of-Birth 2. Amount$Out 3. Section 4. -First-Name 5. 98-6 6. Time out 3-6

7. 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) 3-7

8.  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 3-8

9. Input files Master files Transaction files -> updates Output files New Master files -> mix the two to get Report files 3-9

10. 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 3- 10

11. FD file-name RECORD IS OMITTED LABEL RECORDS ARE STANDARD RECORD CONTAINS integer-1 CHARACTERS BLOCK CONTAINS integer-2 RECORDS. 3- 11

12.  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. 3- 12

13.  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 3- 13

14. 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 3- 14

15. 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. 3- 15

16. REVIEW: SELECT names file, assigns it to hardware device FD describes file 01 names record 02-49 describes fields within record 3- 16

17.  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 3- 17

18. 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 3- 18

19. 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 3- 19

20. Specify type of data stored in field Indicate size of field 3- 20

21. 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 3- 21

22. A for alphabetic X for alphanumeric 9 for numeric 3- 22

23. Denote size of field by:  Number of A’s, X’s or 9’s used in PICTURE 01 Cust-Rec-In. 05Cust-ID-InPicture XXXX. 05Amt-InPicture 99999. 3- 23

24. My also denote size of field by:  A, X or 9 followed by number in parentheses 01 Cust-Rec-In. 05Cust-ID-InPicture X(4). 05Amt-InPicture 9(5). 3- 24

25.  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 3- 25

26.  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. 3- 26

27. 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 3- 27

28. 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 3- 28

29. 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 3- 29

30. 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' 3- 30

31.  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 3- 31

32.  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 3- 32 Example

33.  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 3- 33 Example

34.  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 3- 34

35.  Rules for user-defined data-names apply  Elementary items: ◦ Must include PICTURE clause ◦ May be assigned initial value with VALUE clause 3- 35

36. To define fields used for  Keyed input and displayed output  Intermediate arithmetic results  Counters and totals  End-Of-File Indicators 3- 36

37.  To define initial value for field  If omitted, field’s value undefined when program begins execution  May be used only in WORKING-STORAGE SECTION 3- 37

38.  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 3- 38

39.  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. 3- 39

40. 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. 3- 40

41.  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 3- 41

42.  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. 3- 42

43. 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'. 3- 43 Example

44.  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 3- 44

45. 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 3- 45

46.  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 3- 46

47.  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 3- 47

48.  Group items are further subdivided  Elementary items are not subdivided  Elementary items have PICTURE clause  Codes X, A, 9, V used to describe data 3- 48

49.  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 3- 49