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Understanding COBOL In a day !!!

2008-09-15

Veena KatiyarQA Engineer

TietoEnator CorporationB & I

veena.katiyar@tietoenator.com

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Table of contents.• Structure of COBOL file .• Cobol areas .• Variable declaration .• Structures .• Level 77 & level 88 .• Sentence .• Paragraph .• Arrays .• Simple cobol program .• RUN STOP .• Decision making .• Arithmetic operators .• Comparision operators .• PERFORM .• Complex cobol program .

• Questions ?

• Thank you !!!

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Structure of COBOL file .

IDENTIFICATION DIVISION.* Specify PROGRAM-ID here .PROGRAM-ID. COBSHL04.

ENVIRONMENT DIVISION.Define environment here.

DATA DIVISION. WORKING-STORAGE SECTION.Define variables here .

PROCEDURE DIVISION.* Write program here.

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Cobol areas

Sequence no. :- First 6 columns , used to be sequence no. of punched cards . Nowadays , it’s not required .

Position 7 :- Place an asterisk here then compiler will treat this row as comment and will not process it .

Area A :- DIVISIONs , paragraphs & SECTIONs must start in this area .

Area B :- Sentences must start here

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Variable declaration & Structures The WORKING-STORAGE SECTION of the DATA DIVISION is used to create

space for the variables of a program.

• 01 STUDENT-AGE PIC 9(2) .• 01 MAX-MARKS PIC 999 VALUE 100 .• 01 STUDENT-NAME PIC X(10) VALUE SPACES.

ACCEPT STUDENT-AGE .DISPLAY STUDENT-AGE .

• 01 STUDENT-REC . 05 FILLER PIC X(5) VALUE “Age” . 05 STUDENT-AGE PIC 9(2) VALUE ZERO.

05 FILLER PIC X(5) VALUE “Marks”. 05 MAX-MARKS PIC 999 VALUE 100 . 05 FILLER PIC x(5) VALUE “Name” . 05 STUDENT-NAME PIC X(10) VALUE SPACES .

ACCEPT STUDENT-AGE .DISPLAY STUDENT-REC .

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Level 77 & Level 88• Level 77 :- A variable that is not a structure can be given a level number

of 77 instead of 01 . 77 YES-NO PIC X. • A level number of 77 indicates to the compiler that the variable named

after the 77 is a simple elementary variable and not a structure.

• Level 88 :- It is a special level number used to improve the readability of COBOL programs and to improve IF tests.

• It does not have a PICTURE, but it does have a value. A level 88 is always associated with another variable and is a condition name for that variable. Here is an example:

01 YES-NO PIC X. 88 ANSWER-IS-YES VALUE "Y".

MOVE “Y” TO YES-NO .IF ANSWER-IS-YES* if YES-NO = “Y” DISPLAY “Value of YES-NO is Y” .

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Sentence & Paragraph

• Paragraph :- starts in area A (8-11) . It’s a group of sentences .

MAIN-PROG .

PERFORM GET-NAME . PERFORM GET-AGE . STOP RUN .

GET-NAME .

DISPLAY “Good Morning !!!”.

DISPLAY “Enter your name”.ACCEPT USER-NAME .

GET-AGE .

DISPLAY “Enter your age” .ACCEPT USER-AGE .

• Sentence :- starts in area B (12 onwards) .

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Arrays

Arrays are used to handle multiple records of same structure type .

01 STUDENT-RECORD . 02 MYTABLE OCCURS 2 TIMES .

05 ST-NAME PIC XXXXX.05 FILLER PIC X(10) VALUE SPACES.

05 ST-AGE PIC 99. PROCEDURE DIVISION . DISPLAY "Enter Student name [1] : ". ACCEPT ST-NAME(1) . DISPLAY "Enter Student age [1] : " . ACCEPT ST-AGE(1) .

DISPLAY MYTABLE(1)

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Simple COBOL Program

IDENTIFICATION DIVISIONPROGRAM-ID. MYFIRST .ENVIRONMENT DIVISIONDATA DIVISIONWORKING-STORAGE SECTION.01 USER-NAME PIC X(5).PROCEDURE SECTION .

MAIN-PROG .

PERFORM GET-NAME . STOP RUN .

GET-NAME .DISPLAY “Enter your name”.ACCEPT USER-NAME .DISPLAY “Welcome “ USER-NAME .

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RUN STOP

01 MYNO PIC 9. 88 MYNO-ODD VALUES 1 3 5 7 9. 88 MYNO-EVEN VALUES 2 4 6 8 . 88 MYNO-ZERO VALUE 0.

PROCEDURE DIVISION.

DISPLAY "Enter any no. between 0 to 9 ".ACCEPT MYNO .

IF MYNO-ODD DISPLAY "It's a odd no."

STOP RUN .IF MYNO-EVEN DISPLAY "It's a even no.“

STOP RUN .IF MYNO-ZERO DISPLAY "It's zero“ STOP RUN .STOP RUN ends the execution at the end of the paragraph .

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Decision making

• IF :- DISPLAY “Enter Y or N”.ACCEPT YES-NO .

IF YES-NO = “Y”DISPLAY ”You have entered Y”.

IF YES-NO = “N”DISPLAY ”You have entered N”.

• IF-ELSE :-IF YES-NO = “Y”

DISPLAY “You have entered Y”ELSE

DISPLAY “You have not entered Y” .

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Arithmetic operations• Addition :-

COMPUTE SALARY = SALARY + 1000 .ADD 1000 TO SALARY .ADD 1000 TO 5000 GIVING SALARY .* SALARY = 1000 + 5000

• Subtraction :- COMPUTE SALARY = SALARY – 1000. SUBTRACT 1000 FROM SALARY . SUBTRACT 1000 FROM 5000 GIVING SALARY .* SALARY = 5000 – 1000 .

• Multiplication :- COMPUTE SALARY = SALARY * 1000 . MULTIPLY 1000 BY SALARY . * SALARY = SALARY * 1000 . MULTIPLY 1000 BY 10 GIVING SALARY . * Salary = 1000 * 10 .

• Division :-COMPUTE SALARY = SALARY / 1000 .DIVIDE 10 INTO SALARY.DIVIDE 17 INTO 1000 GIVING SALARY REMAINDER MY-REMAINDER .*SALARY = 1000 / 17 .* Remainder in MY-REMAINDER variable .

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Comparision Operators

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PERFORM• Paragraphs are similar to functions .• PERFORM execute paragraphs .

PROCEDURE DIVISION .MOVE 10 TO A B .

PERFORM ADD-IT 10 TIMES .STOP RUN .

MOVE 10 TO A B .PERFORM ADD-IT UNTIL B >100 .STOP RUN .

PERFORM ADD-IT VARYING A FROM 1 BY 5 UNTIL B > 100 .

ADD-IT .COMPUTE B = A + B .

DISPLAY B.

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Complex COBOL Program IDENTIFICATION DIVISION . PROGRAM-ID . compprog . ENVIRONMENT DIVISION .

DATA DIVISION . WORKING-STORAGE SECTION . 77 UCASE PIC X(26) VALUE "ABCDEFGHIJKLMNOPQRSTUVWXYZ". 77 LCASE PIC X(26) VALUE "abcdefghijklmnopqrstuvwxyz". 01 UTEXT PIC X(20) VALUE SPACES . 01 A-SPACE PIC X(5) VALUE SPACES . 01 CHOICE PIC 9 VALUE ZERO . 01 YESNO PIC X VALUE "Y".

PROCEDURE DIVISION . PERFORM MAIN-PROC UNTIL YESNO = "N".

STOP RUN .

MAIN-PROC . PERFORM GET-DATA . PERFORM GET-CASE.

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PERFORM CHANGE-CASE.PERFORM DISPLAY-DATA .PERFORM ASK-ANOTHER .

GET-DATA . DISPLAY A-SPACE . DISPLAY "Enter text string > ". ACCEPT UTEXT . DISPLAY A-SPACE .

GET-CASE . DISPLAY A-SPACE . DISPLAY "Enter 1 to change to uppercase ." . DISPLAY "Enter 2 to change to lowercase ." . ACCEPT CHOICE . CHANGE-CASE . IF CHOICE = 1

INSPECT UTEXT CONVERTING LCASE TO UCASE ELSE

INSPECT UTEXT CONVERTING UCASE TO LCASE .

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DISPLAY-DATA . DISPLAY A-SPACE . DISPLAY "Result :-". DISPLAY A-SPACE . DISPLAY UTEXT

ASK-ANOTHER . DISPLAY A-SPACE .

DISPLAY "Change another text string [Y/N] ? > ".ACCEPT YESNO .

IF YESNO = "Y" OR YESNO = "y" MOVE "Y" TO YESNO

ELSE MOVE "N" TO YESNO .

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QUESTIONS ???

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Thank you.

Veena KatiyarQA EngineerTietoEnator CorporationB & Iveena.katiyar@tietoenator.com