The purpose of the Environment Division is to isolate in one place all aspects of the program that are dependant upon a specific computer, device or encoding sequence.

The idea behind this is to make it easy to change the program when it has to run on a different computer or one with different peripheral devices.

In the Environment Division, aliases are assigned to external devices, files or command sequences. Other environment details, such as the collating sequence, the currency symbol and the decimal point symbol may also be defined here. The Environment Division has two sections:

• The CONFIGURATION SECTION

The CONFIGURATION SECTION describes the hardware on which the programs to run and on which it is to be compiled. The source computer is the computer on which the program is to be compiled. The object computer is the one on which the program is to run. Additional features of the CONFIGURATION SECTION are:

1. SPECIAL-NAMES

This is used to define mnemonics for printer control.

2. SOURCE-NAMES

Specifies the computer on which the source program is to be compiled.

3. OBJECT-COMPUTER

Describes the computer on which the program is to execute.

• The INPUT-OUTPUT SECTION.

COBOL programs historically get their input from files and write their output to files. Files are thus part of the environment in which a COBOL program runs. In addition most operating systems have naming conventions for files that lead to names that are unacceptable to COBOL. The FILE-CONTROL part of the INPUT-OUTPUT SECTION serves to identify external files by names that are acceptable to the COBOL compiler. COBOL allows many kinds of files we only need sequential files and sort files so that is all that is illustrated.

The first paragraph of the Identification Division must be the PROGRAM-ID paragraph. The other paragraphs are optional, but, when written, must appear in the order shown in the format.

Format Identification Division

IDENTIFICATION DIVISION.

PROGRAM-ID. (mandatory)

AUTHOR. (optional)

INSTALLATION. (optional)

DATE-WRITTEN. (optional)

DATE-COMPILED. (optional)

SECURITY. (optional)

• PROGRAM-ID

Specifies the name of the COBOL program.

• AUTHOR

Name of the author of COBOL the program.

• INSTALLATION

Name of the company or location.

• DATE-WRITTEN

Date the program was written.

• DATE-COMPILED

Date the program was compiled.

• SECURITY

Level of confidentiality of the program.

Enter the line number, COBOL statement, and procedure identifier in the edit screen, as shown in the following example.

• Sequence number area (columns 1 to 6)

Specify the line number in the sequence number area. The line number can be omitted.

• Indicator area (column 7)

Use the indicator area when continuing a line or to change a line to a comment line. In all other cases, be sure to enter a space.

• Area A (columns 8 to 11)

Normally, COBOL divisions, sections, paragraphs and end program headers are described in this area. Data items whose level-number is 77 or 01 are also described in this area.

• Area B (column 12 and on)

Normally, COBOL statements, comment-entries and data items whose level-number is not 77 or 01 are described in this area.

• Line feed character (end of line)

Enter a line feed character at the end of each line.

• TAB character

A TAB character can be specified as the nonnumeric literal in a COBOL source program. The TAB character takes up 1 byte within the non-numeric literal.

After creating and editing the source program, store the program in a file. Normally, you affix the extension COB or CBL to the name of the file.

A “Hello World” program is a computer program that prints out “Hello world!” on a display device. A “hello world” program has become the traditional first program that many people learn.

       IDENTIFICATION DIVISION.

       PROGRAM-ID.  HELLO.

       AUTHOR.      MAKIKI.

       ENVIRONMENT DIVISION.

       DATA DIVISION.

       PROCEDURE DIVISION.

       MAINLINE.

           DISPLAY 'Hello world!'.

           STOP RUN.

This program simply prints out the message “Hello world!”

Source Code