Standards

The COBOL language adheres to ISO standards.

Input and output files

Input and output files are defined in the INPUT-OUTPUT section of the ENVIRONMENT DIVISION.

Data structure: data items and group items

Related data items can be parts of a hierarchical data structure. A data item that does not have any subordinate items is called an elementary data item. A data item that is composed of subordinated data items is called a group item. A record can be either an elementary data item or a group of data items.

COBOL program types

A COBOL source program is a syntactically correct set of COBOL statements. COBOL programs can be of different types:

• Nested program, a program that is contained in another program.
• Object deck, a set or group of executable machine language instructions and other material designed to interact with data to provide problem solutions. An object deck is generally the machine language result of the operation of a COBOL compiler on a source program.
• Run unit, one or more object decks that interact with one another and that function at run time as an entity to provide problem solutions.
• Sibling program, a nested program that is at the same nesting level as another nested program in the same containing program.