Cobol Quiz1 Ch1-2

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  1. Cobol
    Common business oriented language
  2. been in use since
    the 1960's
  3. Record Format
    • Col 1-6:  card sequence number, not often used any more
    • Col 7:  control character
    •    * comment record
    •    D debug record
    •    - literal continuation
    • Col 8-11: A-area
    •    division, section and paragraph names
    •    FD entries, 01 level numbers
    • Col 12-72: B-area
    •    all other entries
    • Col 73-80: Program identification(compiler ignores)
  4. Col1-6
    • Col 7
    • Col1-6: card sequence number
    • Col7: * comment
    •       D debug record
    •       - literal
  5. Col 8-11
    • Col 12-72
    • Coll73-80
    • Col 8-11: A area
    •        divisions, section, paragraph names
    •        FD entries, 01 level numbers
    • Col 12-72: B-area
    •                all other code
    • Coll73-80: Program identification
    •                compiler ignores
  6. main divisions
    • Identification: program name and comments
    • Environment: file references to external OS file name
    •    eg People.dat F01-PEOPLE-FILE
    • DATA: define variables
    •    File section: defines input record and output record
    •       input has 3 field: name, address, age
    •       output contains: name, age
    •    Working Storage section: all other variable declarations
    • Procedure: define the program logic
  7. blanks
    • are use to separate names and commands
    • Multiple blanks are treated as a single blank.
    • Lines can be continued without a continuation character.
  8. Names
    • programmer defined name(paragraph names, variable names) must be:
    • 1 to 30 characters
    • a-z, A-Z, numbers, -
    • not begin or end with -
    • normally begin with letter
    • use meaningful names
    • F01-READ
  9. Variables
    • must have numeric "level number"
    • root variables start with level 01.
    • standard definition is:
    • level# varName format data-value period
    • 01 W01-CUSTOMERNUMBER PIC X(5)
    •          VALUE “ax345”.
    • 01 W02-ADDRESS.
    •    05 W02-STREET PIC X(25)
    •          VALUE “123 Main St.”.
    •    05 W02-CITYPIC X(15)
    •          VALUE “Kingston”.01 W03-AMOUNTOWING PIC 999.
    • CUSTOMERNUMBER is a variable that stores 5 bytes
    • The ADDRESS variable is 40 bytes of memory.
    • AMOUNTOWING stores a number less than 1000.
  10. Picture Clause
    • Define format of variables by defining a picture of what you want, use PIC for short.
    • 9 to define one byte to hold a numeric digit.
    • X to define one byte to hold an alpha-numeric character.
    • V to indicate an “implied decimal”.  To save disk and memory, the period is not stored with the data.
  11. PIC 999999 is same
    • PIC XXXXXXX is same as
    • PIC 99V99 is used to store a number like
    • PIC 999999 is same as PIC 9(6)
    • PIC XXXXXXX is same as PIC X(7)
    • PIC 99V99 is used to store a number like 12.76
  12. Examples of
    • numeric literals:
    • non-numeric literals:

    numeric literals: 17, -893, 47.592
  13. non-numeric literals: "Cat", "613 544 5400"
  14. Procedure Division
    • paragraph.
    • A paragraph starts with a programmer defined name. It can have many statements and sentences.The first paragraph does not need a paragraph name. The last statement in a paragraph must end with a period.
  15. Paragraph Names
    • Name should describe what the paragraph does (its function).
    • should only do ONE function.
    • Use format of “nnn-verb-noun”.
    • Example “100-INITIALIZE-PROGRAM”.
    • Follow every paragraph name with comments to describe the function of paragraph.
  16. Move
    • MOVE statement : copies the data from a sending memory location to a receiving memory location.
    • assignment statement.
    • MOVE sending-var TO receiving-var
    • MOVE “Bob” TO MY-NAME
    • MOVE MY-NAME TO YOUR-NAME
  17. PERFORM
    • will cause a paragraph to be executed (a procedure call).
    • Simple format is:
    •    PERFORM paragraph-name
    • This means go to the paragraph that has this name, execute all the statements in that paragraph, then return to here and fall to the next statement.
  18. Looping
    • A loop is used run code repeatedly until a condition is true.
    • Syntax:
    • PERFORM paragraph-name UNTIL conditional-expression
    • Example:
    • PERFORM 200-PROCESS-RECORD
    •            UNTIL W01-EOF-SWITCH = ‘Y’

    • PERFORM 200-PROCESS-RECORDS
    •      UNTIL W01-DATA-REMAINS-SWITCH = 'NO'
  19. If
    • Syntax:
    • IF conditional-expression
    •       true-statements
    • ELSE
    •     false-statements
    • END-IF
    • Example:
    • IF W01-MY-CITY = ‘Kingston’
    •     MOVE 10.00 TO W02-DELIVERY-FEE
    •     MOVE ‘LOCAL’ TO W02-CARRIER-NAME
    • ELSE
    •     MOVE 25.00 TO W02-DELIVERY-FEE
    •     MOVE ‘UPS’ TO W02-CARRIER-NAME
    • END-IF
    • Programming standards require an END-IF statement to complete the condition.
  20. Continue Statement
    • A Key word/null command: do nothing.
    • Used as a place holder in IF statements.
    • Helpful to allow the asking of a positive question but only do action if it is not true.
    • IF AGE IS NOT NUMERIC
    •     DISPLAY “Bad AGE value”
    • END-IF
    • IF AGE IS NUMERIC
    •     CONTINUE
    • ELSE
    •     DISPLAY “Bad AGE value”
    • END-IF
  21. name the main divisions
    • IDENTIFICATION
    • ENVIRONMENT
    • DATA
    • PROCEDURE
  22. The identification division is
    • The identification division is the first and only
    • mandatory division of every COBOL program.
    • contains program name and author's name.
  23. COBOL program structure
    • program
    •    Divisions
    •       Sections
    •          Paragraphs
    •             Sentences/Statements
  24. file record field
    • field: basic fact
    • record: a set of fields
    • file: a set of records
  25. IDENTIFICATION DIVISION.
    • IDENTIFICATION DIVISION.
    • PROGRAM-ID.    SENIOR.
    • AUTHOR.           ROBERT GRAUER.
  26. ENVIRONMENT DIVISION.
    associates the file names referenced in program to the input and output devices recognized by the OS

    • ENVIRONMENT DIVISION.
    • INPUT-OUTPUT SECTION.
    • FILE-CONTROL.
    •   SELECT F01-STUDENT-FILE ASSIGN
    •      TO 'SENIOR.DAT'
    •           ORGANIZATION IS LINE SEQUENTIAL.
    •   SELECT F02-PRINT-FILE   ASSIGN
    •      TO 'SENIOR.OUT'
    •           ORGANIZATION IS LINE SEQUENTIAL.
  27. template
    • IDENTIFICATION DIVISION.
    • PROGRAM-ID.    PutIDHere.
    • /AUTHOR.           PutYourNameHere.

    • ENVIRONMENT DIVISION.
    • INPUT-OUTPUT SECTION.
    • FILE-CONTROL.
    •     SELECT F01-SomeFile ASSIGN TO
    •                                           'SomeFile.DAT'
    •          ORGANIZATION IS LINE
    •                                    SEQUENTIAL.
    •     SELECT F02-SomeFile ASSIGN TO
    •                                    'SomeFile.OUT'
    •                     ORGANIZATION IS LINE
    •                                    SEQUENTIAL.

    • DATA DIVISION.
    • FILE SECTION.

    WORKING-STORAGE SECTION.

    PROCEDURE DIVISION.

    • STOP RUN
    • .
  28. DATA DIVISION
    describes all the data elements used by the program
  29. FILE SECTION.
    • FILE SECTION.
    • * This is the definition of the input file.
    • FD  F01-STUDENT-FILE
    •       RECORD CONTAINS 43 CHARACTERS
    •       DATA RECORD IS
    •             F01-STUDENT-RECORD.
    • 01  F01-STUDENT-RECORD.
    •       05  F01-STU-NAME            PIC X(25).
    •       05  F01-STU-CREDITS        PIC 9(3).
    •       05  F01-STU-MAJOR           PIC X(15).
    • * This is the definition of the output file.
    • FD  F02-PRINT-FILE
    •       RECORD CONTAINS 132 CHARACTERS
    •       DATA RECORD IS
    •            F02-PRINT-LINE-RECORD.
    • 01  F02-PRINT-LINE-RECORD       PIC X(132).
  30. WORKING-STORAGE SECTION.
    • WORKING-STORAGE SECTION.
    • 01  W01-DATA-REMAINS-SWITCH PIC X(2)
    •                    VALUE SPACES.
    • 01  W02-HEADING-LINE.
    •       05    PIC X(10) VALUE SPACES.
    •       05    PIC X(12) VALUE 'STUDENT NAME'.
    •       05    PIC X(110) VALUE SPACES.
    • 01  W03-DETAIL-LINE.
    •      05    PIC X(8) VALUE SPACES.
    •      05 W03-PRINT-NAME PIC X(25).
    •      05    PIC X(99)     VALUE SPACES.
  31. Reserved words
    • also called figurative constants
    • SPACE SPACES
    • ZERO ZEROS
    • QUOTE QUOTES
    • HIGH-VALUE HIGH-VALUES
    • LOW-VALUE LOW-VALUES
  32. generating blank lines
    • MOVE SPACES TO F02-PRINT-LINE
    • WRITE F02-PRINT-LINE
    • on mainframe
    • BEFORE ADVANCING x LINES
    • AFTER ADVANCEING x LINES
  33. Screen I/O
    • DISPLAY "What is your favourite band?"
    • To receive keyboard input:
    • ACCEPT W01-BAND
  34. READ
    • READ F01-STUDENT-FILE
    •     AT END MOVE 'NO' TO W01-DATA-REMAINS-SWITCH
    • END-READ
  35. Hierarch
    • PROCEDURE DIVISION.
    • 100-HOUSEKEEPING
    •    110-PRINT-HEADINGS
    •    120-PRIME-READ
    • 200-MAINLOOP
    •    210-DO-MATH
    •    220-PRINT-DATA
    •    230-GET-INPUT
    • 300-FINALIZE

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slc53
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327484
Filename:
Cobol Quiz1 Ch1-2
Updated:
2017-03-20 16:21:52
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Cobol Quiz1 Ch1
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Cobol Quiz1 Ch1-2
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