Identification Division and Environment Division

Learning goals

After studying this lesson, learners should be able to:

1. Read instruction-format notation used in COBOL references.
2. Write the basic syntax of the Identification Division.
3. Explain the purpose of the Environment Division.
4. Use FILE-CONTROL and SELECT ... ASSIGN TO for file assignments.

Reading COBOL syntax formats

COBOL references often use special formatting conventions:

Example:

PROGRAM-ID. program-name.

This means PROGRAM-ID. is typed as shown, while program-name is replaced by the chosen program name.

Identification Division

The Identification Division names and identifies the program. In many beginner programs, the only required paragraph is PROGRAM-ID.

Basic form:

       IDENTIFICATION DIVISION.
       PROGRAM-ID. program-name.

Older examples may include documentation paragraphs such as AUTHOR, DATE-WRITTEN, or SECURITY, but student-facing study material should avoid personal or institutional identifiers.

Generic example:

       IDENTIFICATION DIVISION.
       PROGRAM-ID. SALES-REPORT.

Environment Division

The Environment Division describes external resources used by the program, especially files and machine-related details.

Common parts:

       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       SOURCE-COMPUTER. computer-name.
       OBJECT-COMPUTER. computer-name.

       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT file-name ASSIGN TO "external-file-name".

In many simple modern learning examples, the CONFIGURATION SECTION may be omitted unless the compiler requires it. The INPUT-OUTPUT SECTION is important when the program reads or writes files.

Configuration Section

The Configuration Section may document the source and object computers:

• SOURCE-COMPUTER - the machine used to compile the program.
• OBJECT-COMPUTER - the machine used to run the program.
• SPECIAL-NAMES - optional special device or symbolic-name definitions.

Generic example:

       CONFIGURATION SECTION.
       SOURCE-COMPUTER. GENERIC-PC.
       OBJECT-COMPUTER. GENERIC-PC.

Input-Output Section

The Input-Output Section connects COBOL file names to external files or devices.

The most common paragraph is FILE-CONTROL.

       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT STUDENT-FILE
               ASSIGN TO "STUDENT.DAT".
           SELECT REPORT-FILE
               ASSIGN TO "REPORT.TXT".

Internal file name vs. external file name

A COBOL program often uses two names for a file:

Tips for file names

Use meaningful names that describe the file's role:

• SALES-INPUT
• SALES-REPORT
• STUDENT-FILE
• PAYROLL-OUTPUT

Avoid names that are too vague, personal, or unrelated to the program.