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CPSC3111/CISM3111 COBOL

CPSC3111/CISM3111 COBOL. Structured COBOL Programming Text: murach’s structured COBOL Authors: Murach, Prince, Menendez. What is a Computer?. Components of a Computer Input Unit(s); Keyboard, tape, disks Output Unit(s); CRT, tape, disks Memory (Storage) units [Addresses]

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CPSC3111/CISM3111 COBOL

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  1. CPSC3111/CISM3111 COBOL Structured COBOL Programming Text: murach’s structured COBOL Authors: Murach, Prince, Menendez

  2. 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

  3. 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, … • Compiler’s job - translate ‘source’ language to machine language (or ‘byte’ code)

  4. Online vs Interactive • Off-line = batch • Local Batch • Remote Batch • Online = Interactive • Many users with terminals (PC’s) • Can be either local or remote • Single/Multiple User - Timesharing

  5. 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’

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

  7. 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

  8. 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)

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

  10. Identifier Rules • 30 Character Maximum • A-Z, a-z, 0-9, ‘-’ Characters • ‘-’ not first or last character • Usually at least 1 alphabetic

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

  12. 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

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

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

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

  16. 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).

  17. WORKING-STORAGE • WORKING-STORAGE SECTION. • Program’s ‘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

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

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

  20. 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

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

  22. 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

  23. 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

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

  25. PERFORM • PERFORM Paragraph-name • PERFORM Paragraph-name • UNTIL Condition • PERFORM 100-READ-INPUT • PERFORM 300-PROCESS-DATA • UNTIL EOF-FLAG = “YES”

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

  27. Decisions - Simple • IF Condition-1 • True Statements • END-IF

  28. Relational Conditions • > GREATER THAN • < LESS THAN • = EQUAL TO • >= GREATER OR EQUAL • <= LESS OR EQUAL • NOT can be used with all of the above

  29. Decisions - ELSE • IF condition-1 • True Statements • ELSE • False Statements • END-IF

  30. Decisions - Examples • IF HOURS-WORKED > 40 • PERFORM 350-CALC-OVERTIME • ELSE • PERFORM 360-CALC-REGTIME • END-IF

  31. Decisions - complex • IF complex-condition • True statements • ELSE • False statements • END-IF

  32. Complex - conditions • Two or more simple conditions connected with ‘AND’ or ‘OR’. • IF (DEPARTMENT = 234 AND • HIRE-DATE < “96-06-01”) • ADD 1 TO OVER-5-YEARS • END-IF

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

  34. GOBACK / STOP RUN • GOBACK. • (Returns to ‘calling’ entity.) • STOP RUN. • (Returns to Operating System)

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