A Beginner's Week in COBOL👩‍💻

3RD WEEK: -

Hey everyone!!!!!!!!!!!!!!! hope you all are doing well, so in this week I’ve learnt these 3 things: -

1. INTODUCTION

2. COBOL PROGRAM HIERARCHY AND DIVISIONS

3. COBOL Coding Sheet

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1. INTRODUCTION 👀

   - COBOL stands for COMMON BUSINESS ORIENTED LANGUAGE.

   - Used for writing application programs, not for system software.

   - We use PDS file for writing COBOL programs, rules: -

   • The Record Length—>80.

   • The Record Format—>FB.

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2.A COBOL PROGRAM HIERARCHY 🌳

- The COBOL hierarchy looks like this: -

COBOL program

Division

Section

Paragraph

Sentence

Characters

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2.B COBOL PROGRAM DIVISIONS 🐛

- The divisions are divided into 4 parts: -

• Identification Division

  - Used by the compilers and programmers to identify the program.

  - Contains PARAGRAPHS, No SECTIONS. (Every line in this division is PARAGRAPH)

  - Under this division, we’ll have PROGRAM-ID. (only mandatory paragraph)

  - PROGRAM-ID specifies the name of the program. (1-30 characters)

• Environment Division

  - Consists of 2 sections: -

  —>Configuration Section: provides info about the system, the program is written and

  executed.

  - Consists of 2 paragraphs: -

  ~Source Computer- used to compile the program.

  ~Object Computer- used to execute the program.

  —>Input/Output Section: provides info about the files, used in the program.

  • Consists of 2 paragraphs: -

    ~File Control- tells COBOL, how to connect to your file, what file it should use,

    how the file is setup, how it should be read.

    ~Input/Output Control- provides info of files used in the program.

• Data Division

  - used to define variables used in the program.

  - this optional, required only when at least 1 var is declared under this section.

  - consists of 3 sections: -

  • File section- used to define the structure of files. (like what each record looks like)

  • Working-storage section- this is where you define variables, you’ll use in your program.

    - These variables keep their values as long as the program is running.

  • Linkage section- used when another program is calling your program or if your program is

    a sub-program.

    - It allows data to be passed from another program.

• Procedure Division

  - Contains the actual code and logic of the program.

  - Begins in Area-A, and all its statements begins in Area-B.

• Stop Run

  - when stop run is executed, control returns to the O.S.

  - doesn’t have any parameters.

  - should be last executable statement.

  - always be coded in main program.

  - if coded in sub-programs, control returns to the main program.

• Exit Program

  - indicates the end of the sub-program processing and returns control to the main program.

  - mainly used in COBOL sub programs.

  - should be last in seq of statements.

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***IMP points to remember***

📌Hi COBOL in command line—→ Highlights all COBOL verbs in RED.

📌After paragraph heading, should give 1 space.

📌Whatever is written b/w IDENTIFICATION to SECURITY—→ definition of identification division.

📌Every COBOL program should end with STOP RUN.

📌Instead of STOP RUN, can write EXIT PROGRAM/GO BACK.

📌If we miss STOP RUN/EXIT PROGRAM/GO BACK, we don’ get any compilation issue, instead

result in run time abend (U4038).

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3.A COBOL Coding Sheet

- Also known as COBOL reference sheet.

- contains 80 columns.

• 1-6 columns: SEQUENCE NUMBER AREA

  - first 6 characters reserved for seq number.

  - automatically increases with every addition of a new line.

  - COBOL compiler doesn’t consider this column as a part of code.

  - this area is divided into 2 parts: -

  —→ 1-3 —>current page no.

  —→4-6 —>current line no. on the page.

• 7th column: INDICATOR AREA

  - reserved for special characters like: -

  —→ * (Comment Indicator)- if coded, COBOL compiler considers that line as a comment

  —→ - (Continuation Indicator)- current line is the continuation of the previous line.

  —→ / (Print Stopper Indicator)- the printing should start from the new page.

  —→ D (Debugging Indicator)- used for debugging purposes.

• 8-11 columns: Area-A

  - All division names, section names, system defined paragraph names, user defined

  paragraph names, level numbers (01,77), declaratives, non-declaratives, FD/SD entries.

• 12-72 columns: Area-B

  - COBOL verbs, sentences, and statements.

• 73-80 columns: System Generated Numbers

  - reserved for system generated numbers.

  - used for identification purpose.

  - COBOL compiler does not consider these columns as a part of code.