Mainframes

Explanation of Identification Division

A Division is a block of code, which contains one or more sections or set of sections or set of sentences or block of statements.

It begins with division name and ends at the beginning of the next division or at the end of the program.

Divisions are known as system defined words.

All Divisions should be coded in AREA A.

Identification Division provides the program name and other items used to uniquely identify the program.
This division is required in every COBOL program.

In other words, the identification is used to identify the programmer who has write program and it may contain optional
entries like Author,Installation, Date-written, Date-compiled and security depending on the requirement.

PROGRAM-ID is a keyword and it must be specified immediately after the identification division and it is mandatory
in COBOL PROGRAM.

Program name can be up to 8 Characters MAXIMUM.

All the entries in Identification Division should be coded in AREA A.

The Complete syntax of the Identification Division is as follows.

Syntax:

[Mandatory] Identification Division.

[Mandatory] Program-id. Name of the Program.

[Optional] Installation. Development-Center.

[Optional] Date-Written. mm/dd/yy.

[Optional] Date-Compiled. mm/dd/yy. HH:MM:SS.

[Optional] Security. Program-type.


Program- id:

The name of the program will be updated with program-id.

The Length of the program name is up to 8 characters maximum.

By using the program name provided with program-id, the load module will be created after the compilation.

To Execute the program, the name provided with program-id needs to be provided in JCL or in PPT enteries.

The actual source name and name provided with program-id may not be same in all cases.

This is a Mandatory entry(Program-id).


Author:

It describes the name of the programmer who written the program.

This is comment entry which is set of character from the computer character set.

The Comment entry can be written any number of lines before starting another statement in AREA A.

This is optional in Identification Division.


Installation:

It describes the name of the location or company where they installed.

This is also a comment entry.

This is optional in Identification Division.


Date-Written:

It describes the actual date of the program written.

This is also a comment entry.

This is optional in Identification Division.


Date-Compiled:

It describes the actual date of the program compiled.

Date-Compiled details are automatically written by the compiler during the compilation time.

This is also a comment entry.

This is optional in Identification Division.


Security:

The Security describes the confidentiality level of the program.

This is also a comment entry.

This is optional in Identification Division.


Practical Example:

A Simple Program with all entries of identification division was coded like below.


Program Code:

Identification Division.

Program-id. FIRST.

Author Ajay.

Installation SEPT 2015.

Date-Written 06/06/2016.

Date-Compiled. 06/06/2016.

Security Private.

Environment Division.

Data Division.

Procedure Division.

Display 'Identification Division with all entries'.
stop run.

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Structure of COBOL Program

The Structure of the Cobol applies for COBOL Source Program which has set of syntactically correct set of statements.

In other words, COBOL Source Program contains set of syntactically correct set of statements.

Cobol Programs contains hierarchical in structure which was shown in the above diagram.

The COBOL Program hierarchy consists of Divisions, Sections, Paragraphs, Sentences and Statements.

In other words, Each division may contain one or more sections, Each section may contain one or more paragraphs,
Each paragraph contains one or more sentences and each section contains one or more statements.

Each element of the hierarchy consists of one or more subordinate elements.

Divisions➤Sections➤Paragraphs➤Sentences➤Statements.

Discuss them in reverse order for better understanding

Statements:

It consists of a COBOL verb and an operand or operands describes about COBOL verb process on the operands either
it may be a conditional or unconditional.

A statement should have COBOL verb with an operand and may or may not marked with period at the end.

All statements should be code in the AREA B and should not in AREA A.

There are four categories of statements in COBOL.

1. Imperative

2. Conditional

3. Delimited Scope

4. Compiler directing

Example: ADD A TO B GIVING C.

Sentences:

As stated above, a sentence contains one or more statements and those are marked with a period at the last line.

If those are marked with a period in middle, then it will be treated as statement and those are not considered
as sentence.

All sentences also should code in AREA B not in AREA A.

Example:

Move P to Temp
Move Q to P
Move temp to Q.



Paragraphs:

It is a block of code which contains one or more sentences or a set of statements.

A Paragraph begins with the paragraph name and ends at the next paragraph starting.

A Paragraph can be ended in another way at another section starts or at the end of the program.

All paragraphs should code in the AREA A.

Syntax: Paragraph-name.


Sections:

It is a block of code which contains one or more paragraphs or a set of sentences or a block of statements.

Section begins with the section name and ends at another section starting or at the end of the program.

All Sections should code in the AREA A.

Syntax: (section-name) SECTION.


Divisions:

It is a block of code which contains one or more sections or a set of sections or set of sentences or a block of statements.

Division begins with the division name and ends at another division starting or at the end of the program.

All divisions should code in the AREA A.

There are four divisions in COBOL

1. Identification Division.

2. Environment Division.

3. Data Division.

4. Procedure Division.

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