📝 COBOL Coding Rules

📏 COBOL Coding Structure Breakdown

Column Range	Area	Purpose
1–6	Sequence/Tag Area	Optional area for sequence numbers; mostly used in traditional coding sheets and some IDEs for sorting/line tracking.
7	Indicator Area	Special indicators: * (comment), - (continuation), / (new page), D (debugging line).
8–11	Area A	Divisions, Sections, Paragraphs, FD entries, and level numbers (like 01, 77) must begin in this area.
12–72	Area B	COBOL executable statements, clauses, and data entries not starting in Area A must begin here.
73–80	System Use Area	Generally reserved for system-generated information; not used in modern editors.

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📘 Rules to Write COBOL Divisions, Sections, Paragraphs, Sentences, Statements, and Clauses

🔹 Division

• Must start in Area A.

• Only four predefined divisions: IDENTIFICATION, ENVIRONMENT, DATA, PROCEDURE.

• Must be written in upper case, and the spelling must be exact.

• Divisions must follow a fixed order.

🔹 Section

• Appears within a Division (mostly in PROCEDURE and DATA divisions).

• Section names must begin in Area A.

• Ends when another Section or Division begins.

• Optional in small programs, but useful for organizing code into logical blocks.

🔹 Paragraph

• Begins in Area A with a user-defined name followed by a period (.).

• Groups related COBOL statements under one label.

• Paragraph ends when the next paragraph or section starts.

• Commonly used in the PROCEDURE DIVISION.

🔹 Sentence

• A sentence is a group of one or more statements ending with a period (.).

• Begins in Area B.

• Sentences exist only in the PROCEDURE DIVISION.

🔹 Statement

• A single COBOL instruction (e.g., MOVE, DISPLAY, PERFORM).

• May stand alone as a sentence or be part of a longer sentence.

• Starts in Area B, and ends with a period if it is the final statement in a sentence.

🔹 Clause

• A part of a statement that provides additional meaning or constraints.

• Examples include PIC, VALUE, OCCURS in data declarations.

• Clauses do not end with periods and are typically separated by spaces or commas.