CPSC3111CISM3111 COBOL

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CPSC3111/CISM3111 COBOL

• Structured COBOL Programming
• Text murachs structured COBOL
• Authors Murach, Prince, Menendez

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What is a Computer?

• Components of a Computer
• Input Unit(s) Keyboard, tape, disks
• Output Unit(s) CRT, tape, disks
• Memory (Storage) units Addresses
• Control Unit (Executes Instructions)
• Arithmetic/Logic Unit (Math and Logic)
• Only understands machine language

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Hardware / Software

• Hardware Physical equipment
• Software Programs, commands, etc.
• System O/S, compilers, utilities, etc.
• Application User or third party supplied.
• Languages Assembler, Basic(VB), Fortran, RPG,
  Easytrieve, C, C, C, Ada, Java,
• Compilers job - translate source language to
  machine language (or byte code)

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Online vs Interactive

• Off-line batch
• Local Batch
• Remote Batch
• Online Interactive
• Many users with terminals (PCs)
• Can be either local or remote
• Single/Multiple User - Timesharing

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Data Organization

• Bit - Binary digIT - on/off or 1/0
• Character - byte (8 Bits)
• Field - One or more Bytes (Characters)
• Record - One or more Fields
• File - One or more Records
• Database - One or more Files
• Usually contains metadata

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Report Components

• Page Heading
• Column Headings
• Report Body
• Possibly with subtotals, etc.
• Summary
• Final totals, summary totals, etc.

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Program Design

• Program
• Sequence of instructions describing actions to be
  taken by the computer
• Flowchart
• Graphical description of program logic
• Uses rectangles, diamonds, ovals, etc
• Pseudocode
• Symbolic representation of program logic
• More ENGLISH-like

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Data Information Needed

• Type and Size
• Types
• Alphabetic (Seldom used A)
• Alphanumeric (X)
• Numeric (Sign and Decimal)
• Binary
• Numeric
• Packed Numeric
• Floating Point, etc. (Compatibility)

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Program Development

• Define problem
• Design test data
• Design program
• Code program
• Compile program
• Test program
• Document Program

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Identifier Rules

• 30 Character Maximum
• A-Z, a-z, 0-9, - Characters
• - not first or last character
• Usually at least 1 alphabetic

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CARD FORMAT

• 01 - 06 Line Numbers (XNU)
• 07 Comment / Debug
• 08 - 11 Margin A
• 12 - 72 Margin B
• 73 - 80 Identification (XNU)

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COBOL Divisions

• IDENTIFICATION DIVISION.
• ENVIRONMENT DIVISION.
• DATA DIVISION.
• PROCEDURE DIVISION.
• Divisions can be divided into SECTIONS
• Sections can be divided into PARAGRAPHS
• Paragraphs are composed of SENTENCES

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IDENTIFICATION

• IDENTIFICATION DIVISION.
• PROGRAM-ID. PROG1.
• All other entries are obsolete
• An in cc07 can be used (Comment)

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ENVIRONMENT

• ENVIRONMENT DIVISION.
• INPUT-OUTPUT SECTION.
• FILE-CONTROL.
• SELECT INPUT-FILE
• ASSIGN TO MYINFILE.
• SELECT PRINT-FILE
• ASSIGN TO MYREPORT.

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ENVIRONMENT (SELECTS)

• SELECT PRINT-FILE ASSIGN TO
• \RMC\DATA\INPUT.DAT.
• (For PC Files)
• SELECT PRINT-FILE
• ASSIGN TO PRINTER-QPRINT.
• (For AS400 Files)

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DATA

• DATA DIVISION.
• FILE SECTION.
• FD INPUT-FILE.
• 01 INPUT-REC.
• 10 FILLER PIC X(80).
• FD PRINT-FILE.
• 01 PRINT-REC.
• 10 FILLER PIC X(132).

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WORKING-STORAGE

• WORKING-STORAGE SECTION.
• Programs scratchpad
• LEVEL NUMBERS 01-49
• 01 STARTS IN COLUMN 8
• 02-49 COLUMN 12 AND UP
• Usually use 05, 10, 15, 20,
• EACH 01 IS A NEW RECORD
• All fields must be specified

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PROCEDURE

• PROCEDURE DIVISION.
• 010-START-HERE.
• (INITIALIZATION)
• (PROCESS CONTROL LOOP)
• (TERMINATION)

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OPEN

• OPEN INPUT file-name
• OPEN OUTPUT file-name
• (Gets files ready for processing)

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ACCEPT

• ACCEPT identifier FROM DATE
• identifier will contain YYMMDD
• ACCEPT identifier FROM TIME
• identifier will contain HHMMSSMS
• (Used to get date and time)
• ACCEPT identifier options
• Gets data from keyboard

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MOVE

• MOVE identifier-1 TO identifier-2
• (Alpha - Left Just. - Space Filled)
• (Numeric - decimal aligned)
• (Edited - follows edit characters)

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READ

• READ file-name into WS-name
• AT END
• ANY IMPERATIVE STATEMENT(S)
• END-READ
• READ INPUT-FILE INTO WS-IN-REC
• AT END
• MOVE YES TO EOF-FLAG
• END-READ

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WRITE (Generic)

• WRITE record-name FROM ws-name
• AFTER ADVANCING identifier LINES
• END-WRITE
• WRITE PRINT-REC FROM WS-PRINT-REC
• AFTER ADVANCING WS-SPACING
• END-WRITE

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WRITE (New-Page)

• MOVE SPACES TO PRINT-REC
• WRITE PRINT-REC
• AFTER ADVANCING PAGE
• END-WRITE
• (Used to start new page for heading.)

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PERFORM

• PERFORM Paragraph-name
• PERFORM Paragraph-name
• UNTIL Condition
• PERFORM 100-READ-INPUT
• PERFORM 300-PROCESS-DATA
• UNTIL EOF-FLAG YES

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ADD

• ADD literal TO identifier-1
• ADD 1 TO REC-COUNT
• ADD identifier-1 TO identifier-2
• ADD WS-SPACING TO WS-LINES

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Decisions - Simple

• IF Condition-1
• True Statements
• END-IF

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Relational Conditions

• gt GREATER THAN
• lt LESS THAN
• EQUAL TO
• gt GREATER OR EQUAL
• lt LESS OR EQUAL
• NOT can be used with all of the above

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Decisions - ELSE

• IF condition-1
• True Statements
• ELSE
• False Statements
• END-IF

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Decisions - Examples

• IF HOURS-WORKED gt 40
• PERFORM 350-CALC-OVERTIME
• ELSE
• PERFORM 360-CALC-REGTIME
• END-IF

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Decisions - complex

• IF complex-condition
• True statements
• ELSE
• False statements
• END-IF

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Complex - conditions

• Two or more simple conditions connected with
  AND or OR.
• IF (DEPARTMENT 234 AND
• HIRE-DATE lt 96-06-01)
• ADD 1 TO OVER-5-YEARS
• END-IF

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CLOSE

• CLOSE file-name
• CLOSE INPUT-FILE
• (Terminate file processing.)

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GOBACK / STOP RUN

• GOBACK.
• (Returns to calling entity.)
• STOP RUN.
• (Returns to Operating System)