About this book:

Whether you are new to programming or looking to add a critical skill to your résumé, this book gives you a complete, hands‑on introduction to COBOL, the language that still powers the world’s financial, governmental, and insurance systems. You will begin by exploring COBOL’s surprising history—from its creation in the late 1950s to its role in today’s cloud‑native deployments—so you understand why over 200 billion lines of COBOL code remain in production and why mastering it can make you indispensable in industries where accuracy and reliability are non‑negotiable.

The guide walks you through setting up a modern COBOL environment on your own laptop using the free GnuCOBOL compiler, writing your first “Hello, World” program, and then building a solid foundation in COBOL’s unique program structure. You will learn the four mandatory divisions—IDENTIFICATION, ENVIRONMENT, DATA, and PROCEDURE—and see how they enforce clarity and maintainability. Chapters on data types, variables, literals, and constants teach you to declare everything with precision, avoiding the hidden bugs that can cost billions in real‑world applications.

Once the basics are in place, you will dive into the core of COBOL programming: performing arithmetic with exact decimal precision, handling input and output through DISPLAY, ACCEPT, and file operations, and controlling program flow with PERFORM loops, IF‑THEN‑ELSE statements, and the powerful EVALUATE verb. You will gain practical experience reading and writing sequential files, creating indexed and relative files for fast look‑ups, sorting and merging data with the SORT and MERGE verbs, and organizing code into reusable subroutines and modular subprograms. Throughout, the book emphasizes defensive techniques—data validation, error handling with FILE STATUS and INVALID KEY clauses, and debugging strategies that turn cryptic abends into solvable puzzles.

Finally, you will discover how COBOL has evolved to meet modern demands, integrating with JSON, REST APIs, and cloud platforms while retaining its legendary stability. By studying best practices, coding standards, and real‑world case studies—from payroll calculators to transaction rollback systems—you will finish the book not only able to write and maintain COBOL code but also equipped to explain its enduring value to teammates, managers, and auditors. This is more than a language tutorial; it is a pathway to a niche skill set that remains in high demand across the globe.

What You'll Find Inside:

• Discover why COBOL remains critical to global finance, government, and insurance systems despite its age, with over 200 billion lines still in production today
• Master COBOL's structured four-division program architecture (IDENTIFICATION, ENVIRONMENT, DATA, PROCEDURE) that enables half-century system maintainability
• Learn to set up a modern COBOL development environment on Windows, macOS, or Linux using free tools like GnuCOBOL
• Gain proficiency in COBOL fundamentals: data types, variables, arithmetic operations, control structures, and file handling
• Explore advanced topics including sorting/merging data, subroutines, error handling, and modern COBOL integration with cloud and APIs

Who's It For:

This book is ideal for absolute beginners to COBOL programming, including new developers entering the workforce, experienced programmers from other languages seeking to maintain legacy systems, and IT professionals working in finance, government, or insurance sectors who need to understand or modify COBOL-based applications. It provides the perfect foundation for anyone looking to gain skills in a language that still powers critical business infrastructure worldwide.