Educational

Author: Saim Khalid

  • WORKING STORAGE SECTION and LINKAGE SECTION?

    WORKING-STORAGE: Declares variables for the current program.

    LINKAGE SECTION: Declares variables that come from another program or JCL (passed parameters).

  • PERFORM and CALL?

    • PERFORM → used for executing a paragraph or section within the same program (like a loop or subroutine).
    • CALL → used for calling an external program or subprogram.

    Example:

    PERFORM CALC-PARA.      *> internal call

CALL 'SUBPROG' USING VAR1.  *> external program call

  • What is PIC clause in COBOL?

    • PIC stands for Picture Clause → defines the type & size of a variable.

    Example:

    01 NAME  PIC A(10).    *> 10 characters (Alphabetic)
01 AGE   PIC 9(3).     *> 3-digit number
01 SALARY PIC 9(5)V99. *> 5 digits + 2 decimal places

  • COMP and COMP-3?

    • COMP (Binary Storage): Data stored in pure binary format. Faster for arithmetic operations.
    • COMP-3 (Packed Decimal): Data stored in packed format (2 digits per byte). Saves space, often used in financial apps.

    Example:

    01 A  PIC 9(4) COMP.     *> Binary storage
01 B  PIC 9(4) COMP-3.  *> Packed decimal storage

  • divisions in COBOL program?

    COBOL program is divided into 4 divisions:

    1. IDENTIFICATION DIVISION – program info (name, author).
    2. ENVIRONMENT DIVISION – environment details (input-output devices).
    3. DATA DIVISION – data & variables declaration.
    4. PROCEDURE DIVISION – actual logic/code.

    Example:

    IDENTIFICATION DIVISION.
PROGRAM-ID. SAMPLE.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 NUM PIC 9(3).
PROCEDURE DIVISION.

    DISPLAY "HELLO".
STOP RUN.

  • Loop (Perform Until)

      IDENTIFICATION DIVISION.
   PROGRAM-ID. LOOP-DEMO.

   DATA DIVISION.
   WORKING-STORAGE SECTION.
   01 COUNTER    PIC 9(2) VALUE 1.

   PROCEDURE DIVISION.

       PERFORM UNTIL COUNTER > 5
       DISPLAY "COUNTER = " COUNTER
       ADD 1 TO COUNTER
   END-PERFORM.
   STOP RUN.</code></pre>
    



    Explanation:
    




    PERFORM UNTIL → loop continues until condition is met.
    




    COUNTER → starts at 1, increments until 5.
    




    Output:
    




    ini
    





    COUNTER = 1
    COUNTER = 2
    COUNTER = 3
    COUNTER = 4
    COUNTER = 5

  • Simple IF ELSE

    IDENTIFICATION DIVISION.
    PROGRAM-ID. CHECK-NUMBER.

       DATA DIVISION.
   WORKING-STORAGE SECTION.
   01 NUM     PIC 9(3).

   PROCEDURE DIVISION.

       DISPLAY "ENTER A NUMBER: ".
   ACCEPT NUM.
   IF NUM &gt; 100
       DISPLAY "NUMBER IS GREATER THAN 100"
   ELSE
       DISPLAY "NUMBER IS 100 OR LESS".
   STOP RUN.</code></pre>
    



     Explanation:
    




    IF NUM > 100 → checks condition.
    




    DISPLAY → shows different messages based on condition.

  • User Input and Display

       IDENTIFICATION DIVISION.
   PROGRAM-ID. USER-INPUT.

   DATA DIVISION.
   WORKING-STORAGE SECTION.
   01 USER-NAME   PIC A(20).

   PROCEDURE DIVISION.

       DISPLAY "ENTER YOUR NAME: ".
   ACCEPT USER-NAME.
   DISPLAY "HELLO, " USER-NAME.
   STOP RUN.</code></pre>
    



    Explanation:
    




    PIC A(20) → allows up to 20 alphabetic characters.
    




    ACCEPT USER-NAME → takes input from user.
    




    DISPLAY → prints greeting with input.

  • Add Two Numbers

       IDENTIFICATION DIVISION.
   PROGRAM-ID. ADD-NUMBERS.

   DATA DIVISION.
   WORKING-STORAGE SECTION.
   01 NUM1     PIC 9(3) VALUE 25.
   01 NUM2     PIC 9(3) VALUE 30.
   01 SUM      PIC 9(4).

   PROCEDURE DIVISION.

       ADD NUM1 TO NUM2 GIVING SUM.
   DISPLAY "THE SUM IS: " SUM.
   STOP RUN.</code></pre>
    



    Explanation:
    




    WORKING-STORAGE SECTION → used to declare variables.
    




    01 NUM1 PIC 9(3) → variable with 3 digits (e.g., 025).
    




    ADD NUM1 TO NUM2 GIVING SUM → performs addition.
    




    DISPLAY → shows result.
    




    Output:

    THE SUM IS: 55

  • Hello World Program

       IDENTIFICATION DIVISION.
   PROGRAM-ID. HELLO-WORLD.
   PROCEDURE DIVISION.

       DISPLAY "HELLO, WORLD!".
   STOP RUN.</code></pre>
    



    Explanation:
    




    IDENTIFICATION DIVISION → declares the program name.
    




    PROGRAM-ID → the name of the program (HELLO-WORLD).
    




    PROCEDURE DIVISION → instructions.
    




    DISPLAY → prints output on screen.
    




    STOP RUN → ends the program.