Learn COBOL with Real Code Examples

COBOL is optimized for business data processing, not system-level or performance-critical tasks.

It features a verbose, English-like syntax designed for readability by non-programmers in the 1960s.

Used extensively in banking, insurance, government, and enterprise legacy systems for decades.

DIVISION-based program structure

Built-in file handling for sequential and indexed data

Extensive record definitions via DATA DIVISION

Procedural logic through PROCEDURE DIVISION

Batch processing and transaction support

Divisions and sections

Variables and data types via PIC clauses

Records and file structures

Procedural flow with PERFORM statements

Batch input/output and file operations

source.cob

copybooks (.cpy)

JCL scripts for batch execution (mainframe)

Compiled binary or mainframe load module

Dataset definitions

Write .cob or .cbl program

Compile using cobc or mainframe compiler

Link libraries (if required)

Run executable locally or submit batch job

Validate results through dataset outputs

Beginner: simple calculations or text output

Intermediate: file processing and record manipulation

Advanced: batch systems with multiple datasets

Expert: full financial transaction systems or mainframe integration

More verbose than modern languages

Far more stable for business logic

Better suited for batch than real-time apps

Strong legacy support vs modern innovation

More maintainable for long-term enterprise systems

1959 – COBOL 60

1974 – COBOL-74 (major standardization)

1985 – COBOL-85 (structured programming)

2002 – Object-oriented COBOL

2014–2025 – Modern compiler support & cloud COBOL

Copybook: reusable data layout file

Division: major program section

Record: structured data unit

Dataset: mainframe data storage

JCL: Job Control Language for batch jobs