COBOL (Common Business-Oriented Language) is one of the oldest high-level programming languages, primarily tailored for business applications. Introduced in the late 1950s, COBOL is designed to handle large volumes of data processing typically found in commercial environments. It features a verbose syntax intended to be self-documenting, which makes it easier for non-programmers to understand the code. Despite being over six decades old, COBOL remains in active use, particularly in legacy systems within banking, government, and insurance sectors.
COBOL was developed in response to the need for a standardized language for business applications. The first meeting to discuss COBOL occurred in 1959, involving a consortium of government and industry representatives. The goal was to create a language that could process business data, which varied widely across different platforms. The first specifications were released in 1960, and its popularity surged in the 1960s as businesses began transitioning from assembly language to high-level programming for more efficient data processing.
The development of COBOL continued through the 1970s and 1980s, with several revisions and enhancements to improve functionality and performance. ANSI standardized COBOL, with updated versions released in 1974, 1985, and 2002. Despite the introduction of more modern programming languages, COBOL maintained a substantial presence in the enterprise realm, partially due to the immense investment in existing COBOL applications.
Today, COBOL is still widely used, especially in mainframe environments. Many legacy systems still run core operations in financial institutions and government sectors. Modern initiatives have attempted to integrate COBOL with contemporary technologies, such as cloud computing and web services. Additionally, efforts like the "COBOL 2020" project aim to modernize the language further, ensuring its relevance in today's technological landscape.
COBOL features a verbose, English-like syntax, which facilitates readability. For example, a simple data declaration might look like this:
01 CUSTOMER-NAME PIC A(30).
COBOL provides several data types, including alphanumeric (A), numeric (9), and decimal (V). A numeric variable definition would appear as:
01 ACCOUNT-BALANCE PIC 9(10)V99.
COBOL programs are divided into four main divisions: Identification, Environment, Data, and Procedure. This division helps to organize the code logically. An example of a program structure:
IDENTIFICATION DIVISION.
PROGRAM-ID. HelloWorld.
ENVIRONMENT DIVISION.
DATA DIVISION.
PROCEDURE DIVISION.
DISPLAY 'Hello, World!'.
STOP RUN.
COBOL has intrinsic support for file operations. File declarations and operations (like OPEN, READ, WRITE) in COBOL are straightforward:
01 CUSTOMER-FILE FILE SECTION.
02 CUSTOMER-RECORD RECORD.
03 CUSTOMER-NAME PIC A(30).
03 CUSTOMER-BALANCE PIC 9(10)V99.
COBOL uses the IF, THEN, and ELSE constructs for conditional logic:
IF CUSTOMER-BALANCE > 1000 THEN
DISPLAY 'VIP Customer'
ELSE
DISPLAY 'Standard Customer'.
The PERFORM statement is used for looping constructs in COBOL:
PERFORM VARYING I FROM 1 BY 1 UNTIL I > 10
DISPLAY I.
COBOL organizes code into paragraphs and sections, which enhances modular programming:
MAIN-LOGIC SECTION.
DISPLAY 'Start of the program'.
END MAIN-LOGIC.
COBOL supports comments, which can take two forms: asterisks in the first column or the * character in code:
* This is a comment
COBOL allows arithmetic operations using the COMPUTE statement:
COMPUTE TOTAL-PRICE = ITEM-PRICE * ITEM-QUANTITY.
COBOL offers string manipulation with operations such as STRING, UNSTRING:
STRING FIRST-NAME DELIMITED BY SPACE
LAST-NAME DELIMITED BY SPACE
INTO FULL-NAME.
Numerous COBOL compilers and interpreters exist today, including Micro Focus COBOL, GnuCOBOL, and Fujitsu COBOL. Each provides varying support for modern features and integration capabilities.
Popular IDEs for COBOL development include Micro Focus Visual COBOL, IBM Rational Developer for System z, and Eclipse with COBOL plugins. These IDEs facilitate easier coding, debugging, and project management.
Typically, a COBOL project involves creating a source file with a .cob extension and compiling it using an appropriate compiler. The build process usually includes compiling the source code into an executable format that can run on a target system.
COBOL is primarily used in sectors where large-scale data processing is essential. Its applications include:
COBOL stands in contrast to general-purpose programming languages like Python, Java, and C#. Its syntax is considerably more verbose, emphasizing readability and business logic over the brevity found in modern languages.
In the realm of programming languages, COBOL emphasizes readability and maintainability, which makes it appealing for industries where clarity and correctness are paramount.
When considering translating COBOL code to other languages, it's essential to focus on the logic structure rather than a line-by-line translation. The concepts of data types, file handling, and procedural programming are crucial to maintain the integrity of business logic.
Several tools can facilitate COBOL to modern language translations or transformations, such as: