Literature Review
COBOL (common business-oriented language) is a high-level programming language for managing financial transactions in applications around the world and on all platforms.
Grace Hopper is considered the grandmother or mother of this language, although she had nothing to do with the development or design of this language. She is called this because COBOL was based on another language, FLOW-MATIC, which she was involved in creating. This language is also called B-0 or Business Language Version 0.
Reasons for the creation and the first version of COBOL, COBOL-60
It all started on May 28-29, 1959, when a meeting was held at the Pentagon to create a common programming language for business. At that time, the most popular language was FORTRAN, but it did not have the necessary functionality to be useful when writing business or financial applications.
At this meeting, 41 people participated, and they concluded that this language should be easy to learn and be applicable in various fields of activity. Starting from the financial sector and ending with inventory management in warehouses.
Later, the committee met again on June 4, 1959, and established the Committee on Data Systems Languages (CODASYL). Then the committee determined all the advantages and disadvantages of the FLOW-MATIC and COMTRAN languages and later developed COBOL based on them. Grace Hopper herself said:
COBOL (an acronym for Common Business-Oriented Language) is a programming language developed in 1959 by a working group composed of elements of the US industry and some US government agencies to create a programming language suitable for processing commercial data. Grace Murray Hopper played a primary role in the development and design of the language.
COBOL is a procedural programming language, business-oriented and with strong typing. Its syntax is verbose and descriptive, trying to approach natural language. A COBOL program is divided into four divisions: identification, environment, data and procedure.
IDENTIFICATION DIVISION.
PROGRAM-ID. COMPOUND-INTEREST.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 INITIAL-AMOUNT PIC 9(5)V99 COMP-3.
01 INTEREST-RATE PIC 9(3)V9 COMP-3.
01 YEARS PIC 9(4) COMP-3.
01 FINAL-AMOUNT PIC 9(7)V99 COMP-3.
PROCEDURE DIVISION.
DISPLAY "Enter the initial amount: "
ACCEPT INITIAL-AMOUNT
DISPLAY "Enter the interest rate (as a percentage): "
ACCEPT INTEREST-RATE
DISPLAY "Enter the number of years: "
ACCEPT YEARS
MOVE INITIAL-AMOUNT TO FINAL-AMOUNT
PERFORM VARYING YEARS FROM 1 BY 1
UNTIL YEARS = 0
COMPUTE FINAL-AMOUNT = FINAL-AMOUNT * (1 + INTEREST-RATE / 100)
DISPLAY "The final amount after " YEARS " years is: " FINAL-AMOUNT
STOP RUN.Traditionally, COBOL programs were written on coding forms and then punched on to punch cards. Although nowadays most programs are entered directly into a computer, some COBOL formatting conventions remain that derive from its ancient punch-card history.
On coding forms, the first six character positions are reserved for sequence numbers. The seventh character position is reserved for the continuation character, or for an asterisk that denotes a comment line.
The actual program text starts in column 8. The four positions from 8 to 11 are known as Area A, and positions from 12 to 72 are Area B.
Although many COBOL compilers ignore some of these formatting restrictions, most still retain the distinction between Area A and Area B.
When a COBOL compiler recognizes the two areas, all division names, section names, paragraph names, FD entries and 01 level numbers must start in Area A. All other sentences must start in Area B.
In our example programs we use the compiler directive (available with the NetExpress COBOL compiler) – $ SET SOURCEFORMAT”FREE” – to free us from these formatting restrictions.
Ancient COBOL coding form
For over four decades COBOL has been the dominant programming language in the business computing domain. In that time it it has seen off the challenges of a number of other languages such as PL1, Algol68, Pascal, Modula, Ada, C, C++. All these languages have found a niche but none has yet displaced COBOL. Two recent challengers though, Java and Visual Basic, are proving to be serious contenders.
COBOL’s dominance in underlined by the reports from the Gartner group.
In 1997 they estimated that there were about 300 billion lines of computer code in use in the world. Of that they estimated that about 80% (240 billion lines) were in COBOL and 20% (60 billion lines) were written in all the other computer languages combined [Brown].
In 1999 they reported that over 50% of all new mission-critical applications were still being done in COBOL and their recent estimates indicate that through 2004-2005 15% of all new applications (5 billion lines) will be developed in COBOL while 80% of all deployed applications will include extensions to existing legacy (usually COBOL) programs.
Gartner estimates for 2002 are that there are about two million COBOL programmers world-wide compared to about about one million Java programmers and one million C++ programmers
COBOL is self-documenting
One of the design goals for COBOL was to make it possible for non-programmers such as supervisors, managers and users, to read and understand COBOL code. As a result, COBOL contains such English-like structural elements as verbs, clauses, sentences, sections and divisions. As it happens, this design goal was not realized. Managers and users nowadays do not read COBOL programs. Computer programs are just too complex for most laymen to understand them, however familiar the syntactic elements. But the design goal and its effect on COBOL syntax has had one important side-effect. It has made COBOL the most readable, understandable and self-documenting programming language in use today. It has also made it the most verbose.
It is easy for programmers unused to the business programming paradigm, where programming with a view to ease of maintenance is very important, to dismiss the advantage that COBOL’s readability imparts. Not only does this readability generally assist the maintenance process but the older a program gets the more valuable this readability becomes.
When programs are new, both the in-program comments and the external documentation accurately reflect the program code. But over time, as more and more revisions are applied to the code, it gets out of step with the documentation until the documentation is actually a hindrance to maintenance rather than a help. The self-documenting nature of COBOL means that this problem is not as severe with COBOL programs as it is with other languages
Readers who are familiar with C or C++ or Java might want to consider how difficult it becomes to maintain programs written in these languages. C programs that you have written yourself are difficult enough to understand when you come back to them six months later. Consider how much more difficult it would be to understand a program that had been written fifteen years previously, by someone else, and which had since been amended and added to by so many others that the documentation no longer accurately reflects the program code. This is a nightmare still awaiting maintenance programmers of the future
COBOL is simple
COBOL is a simple language (no pointers, no user defined functions, no user defined types) with a limited scope of function. It encourages a simple straightforward programming style. Curiously enough though, despite its limitations, COBOL has proven itself to be well suited to its targeted problem domain (business computing). Most COBOL programs operate in a domain where the program complexity lies in the business rules that have to be encoded rather than in the sophistication of the data structures or algorithms required. And in cases where sophisticated algorithms are required COBOL usually meets the need with an appropriate verb such as the SORT and the SEARCH.
We noted above that COBOL is a simple language with a limited scope of function. And that is the way it used to be but the introduction of OO-COBOL has changed all that. OO-COBOL retains all the advantages of previous versions but now includes –
User Defined Functions
Object Orientation
National Characters – Unicode
Multiple Currency Symbols
Cultural Adaptability (Locales)
Dynamic Memory Allocation (pointers)
Data Validation Using New VALIDATE Verb
Binary and Floating Point Data Types
User Defined Data Types
COBOL is non-proprietary (portable)
The COBOL standard does not belong to any particular vendor. The vendor independent ANSI COBOL committee legislates formal, non-vendor-specific syntax and semantic language standards. COBOL has been ported to virtually every hardware platform – from every favour of Windows, to every falser of Unix, to AS/400, VSE, OS/2, DOS, VMS, Unisys, DG, VM, and MVS.
COBOL is Maintainable
COBOL has a 30 year proven track record for application maintenance, enhancement and production support at the enterprise level. Early indications from the year 2000 problem are that COBOL applications were actually cheaper to fix than applications written in more recent languages. [ Capers Jones] [Kappleman]
One reason for the maintainability of COBOL programs has been given above – the readability of COBOL code. Another reason is COBOL’s rigid hierarchical structure. In COBOL programs all external references, such as to devices, files, command sequences, collating sequences, the currency symbol and the decimal point symbol, are defined in the Environment Division.
When a COBOL program is moved to a new machine, or has new peripheral devices attached, or is required to work in a different country; COBOL programmers know that the parts of the program that will have to be altered to accommodate these changes will be isolated in the Environment Division. In other programming languages, programmer discipline could have ensured that the references liable to change were restricted to one part of the program but they could just as easily be spread throughout the program. In COBOL programs, programmers have no choice. COBOL’s rigid hierarchical structure ensures that these items are restricted to the Environment Division