COBOL Tutorial
COBOL stands for Common Business Oriented Language. The US Department of Defense, in a conference, formed CODASYL (Conference on Data Systems Language) to develop a language for business data processing needs which is now known as COBOL.
COBOL is used for writing application programs and we cannot use it to write system software. The applications like those in defense domain, insurance domain, etc. which require huge data processing make extensive use of COBOL.
Audience
This tutorial is designed for software programmers who would like to learn the basics of COBOL. It provides enough understanding on COBOL programming language from where you can take yourself to a higher level of expertise.
Prerequisites
Before proceeding with this tutorial, you should have a basic understanding of computer programming terminologies and JCL. A basic understanding of any of the programming languages will help you understand the concepts of COBOL programming and move fast on the learning track.
What is COBOL and Why is it Important in the Business World?
Common Business Oriented Language (COBOL) is one of the oldest high-level programming languages. It was developed in the late 1950s for business applications and administrative systems. COBOL is known for its readability and easy-to-understand syntax that resembles natural English.
COBOL can run on various platforms including mainframes, Windows, Linux, and Unix systems. The key features of COBOL include its readability, English-like syntax, and strong support for data processing and file handling. COBOL can be integrated with modern technologies such as APIs, web services, and databases. It can also work alongside other programming languages through interoperability features.
Is COBOL Still Relevant Today? What are its Modern-Day Applications?
COBOL is still extensively used in critical business systems. Many organizations rely on COBOL-based systems for transaction processing, payroll systems, and large-scale batch processing. COBOL plays a significant role in mainframe computing, running critical applications in banking, insurance, and government sectors. It is known for its reliability and efficiency in handling large-scale transaction processing. COBOL continues to be relevant for maintaining and updating legacy systems.
To remain relevant, COBOL has been updated with modern programming concepts such as support for structured and object-oriented programming, enhancements in data handling capabilities, and improvements in interoperability with other systems and languages. Today, COBOL applications are not limited to just mainframes; they can run on modern platforms such as Windows, Linux, and cloud environments. COBOL”s adaptability has allowed it to integrate with web services, APIs, and contemporary databases. Its modern-day applications include handling high-volume transactions in banking systems and managing data in healthcare, government, and retail industries.
Why should I Learn COBOL?
One should learn COBOL because it is still widely used in legacy systems, especially in banking, finance, and government sectors. COBOL expertise can lead to job opportunities in maintaining and modernizing these systems.
Key Features of COBOL that Make it Suitable for Business Applications
COBOL has been designed specifically for business applications. Its English-like syntax can be easilly understood, even by business managers with no technical background in programming. COBOL can support complex data structures and precise numerical calculations, which is crucial for financial and administrative tasks.
COBOL has very impressive file-handling features, which makes it so efficient at processing large volumes of data. COBOL”s compatibility with legacy systems ensures that existing applications can continue to operate seamlessly.
Do I need Prior Programming Experience to Learn COBOL?
This tutorial on COBOL is meant for beginners. Although prior programming experience can always be helpful, it is not absolutely necessary to start learning COBOL. Starting with COBOL involves understanding its unique syntax and structure, which are quite different from the modern-day programming languages.
How do I write a Simple COBOL Program?
A simple COBOL program consists of four divisions: IDENTIFICATION, ENVIRONMENT, DATA, and PROCEDURE. You can start by defining the program”s name and structure and then write the necessary code in the PROCEDURE DIVISION.
How can I Practice COBOL Programming?
You can practice COBOL by setting up a development environment, working on sample projects, participating in coding challenges, and contributing to open-source COBOL projects. We have a wonderful “Online COBOL Compiler” that you can use to execute COBOL programs.
FAQs About COBOL
There are some very Frequently Asked Questions(FAQ) about COBOL, this section tries to answer them briefly.
Data types in COBOL define the type of data that can be stored in a variable. Common data types include PIC X for alphanumeric, PIC 9 for numeric, and PIC S9 for signed numbers.
Variables are defined in the DATA DIVISION, specifically in the WORKING-STORAGE SECTION. You use the PIC clause to specify the data type and size.
A paragraph in COBOL is a block of code identified by a name followed by a period. Paragraphs group related instructions and can be executed as a unit.
You can perform arithmetic operations using the ADD, SUBTRACT, MULTIPLY, DIVIDE, and COMPUTE verbs.
In COBOL, a file is a collection of records. Files are used for storing data that a program can read from or write to, typically defined in the FILE SECTION of the DATA DIVISION. You can use the OPEN, READ, WRITE, and CLOSE verbs to manage file operations in COBOL.
A copybook is a reusable code module that contains data definitions. It can be included in multiple programs using the COPY statement.
COBOL control structures include conditional statements (IF, EVALUATE) and loops (PERFORM).
You can use the IF statement for simple conditions and the EVALUATE statement for more complex, switch-like logic.
The PERFORM statement is used to execute a paragraph or section repeatedly, acting as a loop.
Error handling in COBOL can be managed using the FILE STATUS clause for file operations and the INVALID KEY and AT END clauses for other operations.
For working with COBOL, you can use IDEs like Micro Focus Visual COBOL, IBM Rational Developer, and open-source editors like Visual Studio Code with COBOL extensions.
You can debug a COBOL program using tools like IBM Debug Tool, Micro Focus Enterprise Developer, or by adding diagnostic DISPLAY statements in the code.
Generally COBOL is not used for front-end web development, however it can be integrated with web services and back-end systems to support web applications.
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