Presentation on theme: "COBOL LANGUAGE COmmon Business Oriented Language Sarunya Dechasajja 47541487."— Presentation transcript:
COBOL LANGUAGE COmmon Business Oriented Language Sarunya Dechasajja 47541487
BACKGROUND -Developed in 1959 by a group of computer professionals called the Conference on Data Systems Languages (CODASYL) -In 1968 the American National Standards Institute (ANSI) developed a standard form of the language. This version was known as American National Standard (ANS) COBOL. -Object-oriented COBOL is a subset of COBOL 97, which is the fourth edition in the continuing evolution of ANSI/ISO standard COBOL. -Like the C++ programming language, object- oriented COBOL compilers are available even as the language moves toward standardization.
DESCRIPTION OF COBOL LANGUAGE -COBOL is a Third-generation programming language, and one of the oldest programming languages still in active use. -Defining its primary domain in business, finance, and administrative system for companies and governments. -Example of COBOL standard: COBOL-68, COBOL- 74, COBOL-85 and COBOL 2002
DISTINCTIVE CHARACTERISTIC -The language that automated business -Allows names to be truly connotative - permits both long names (up to 30 characters) and word-connector characters (dashes) -Every variable is defined in detail - this includes number of decimal digits and the location of the implied decimal point -File records are also described with great detail, as are lines to be output to a printer - ideal for printing accounting reports -Offers object, visual programming environments -Class Libraries -Rapid Application Capabilities -Integration with the World Wide Web
DISTINCTIVE CHARACTERISTIC COBOL, long associated with green screens, core dumps, and traditional mainframe connections, may at first glance seem at odds with object technology, push-button graphical interfaces, and interactive development environments. This perceived incongruity, however, is more a reflection of the mainframe’s ability to keep pace with the innovations of desktop and client- server computing than a flaw in the COBOL language.
DESIGN GOALS -One goal of COBOL's design was for it to be readable by managers, so the syntax had very much of an English-like flavor. -The specifications were to a great extent inspired by the FLOW-MATIC language invented by Grace Hopper -She then promoted COBOL’s use
CHARACTERISTICS COBOL is a simple language with a limited scope of function(no pointers, no user defined functions, no user defined types ). 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
SAMPLE PROGRAM: Accepts two numbers and adds them together 000100 ID DIVISION. 000200 PROGRAM-ID. ACCEPT1. 000300 DATA DIVISION. 000400 WORKING-STORAGE SECTION. 000500 01 WS-FIRST-NUMBER PIC 9(3). 000600 01 WS-SECOND-NUMBER PIC 9(3). 000700 01 WS-TOTAL PIC ZZZ9. 000800* 000900 PROCEDURE DIVISION. 001000 0000-MAINLINE. 001100 DISPLAY 'ENTER A NUMBER: '. 001200 ACCEPT WS-FIRST-NUMBER. 001300* 001400 DISPLAY 'ANOTHER NUMBER: '. 001500 ACCEPT WS-SECOND-NUMBER. 001600* 001700 COMPUTE WS-TOTAL = WS-FIRST-NUMBER + WS-SECOND-NUMBER. 001800 DISPLAY 'THE TOTAL IS: ', WS-TOTAL. 001900 STOP RUN. Sample Run ENTER A NUMBER: a ANOTHER NUMBER: b THE TOTAL IS: a + b
SAMPLE PROGRAM: Takes all input records of salesperson data and writes it to an output file reformatted 000100 ID DIVISION. 000200 PROGRAM-ID. SLS02. 000300 FILE-CONTROL. 000400 SELECT SALESPERSON-FILE 000500 ASSIGN TO DISK. 000600 SELECT REPORT-FILE 000700 ASSIGN TO PRINTER. 000800 DATA DIVISION. 000900 FILE SECTION. 001000 FD SALESPERSON-FILE. 001100 01 SALESPERSON-RECORD. 001200 05 FILLER PIC XX. 001300 05 SP-NUMBER PIC X(4). 001400 05 SP-NAME PIC X(18). 001500 05 FILLER PIC X(21). 001600 05 SP-CURRENT-SALES PIC 9(5)V99. 001700 05 SP-CURRENT-RETURNS PIC 9(4)V99. 001800 FD REPORT-FILE.
SAMPLE PROGRAM: Takes all input records of salesperson data and writes it to an output file reformatted 001900 01 REPORT-RECORD. 002000 05 FILLER PIC X(10). 002100 05 RT-NUMBER PIC X(4). 002200 05 FILLER PIC X(6). 002300 05 RT-NAME PIC X(18). 002400 05 FILLER PIC X(6). 002500 05 RT-CURRENT-SALES PIC ZZ,ZZZ.99. 002600 05 FILLER PIC X(6). 002700 05 RT-CURRENT-RETURNS PIC Z,ZZZ.99. 002800 05 FILLER PIC X(65). 002900 WORKING-STORAGE SECTION. 003000 01 WS-EOF-FLAG PIC X. 003100* 003200 PROCEDURE DIVISION. 003300* 003400 MAIN-ROUTINE. 003500 OPEN INPUT SALESPERSON-FILE 003600 OUTPUT REPORT-FILE 003700 MOVE "N" TO WS-EOF-FLAG 003800 READ SALESPERSON-FILE 003900 AT END MOVE "Y" TO WS-EOF-FLAG 004000 END-READ
SAMPLE PROGRAM: Takes all input records of salesperson data and writes it to an output file reformatted 004100* 004200 PERFORM UNTIL WS-EOF-FLAG IS EQUAL TO "Y" 004300 MOVE SPACES TO REPORT-RECORD 004400 MOVE SP-NUMBER TO RT-NUMBER 004500 MOVE SP-NAME TO RT-NAME 004600 MOVE SP-CURRENT-SALES TO RT-CURRENT-SALES 004700 MOVE SP-CURRENT-RETURNS TO RT-CURRENT-RETURNS 004800 WRITE REPORT-RECORD 004900 READ SALESPERSON-FILE 005000 AT END MOVE "Y" TO WS-EOF-FLAG 005100 END-READ 005200 END-PERFORM 005300* 005400 CLOSE SALESPERSON-FILE, REPORT-FILE 005500 STOP RUN. Sample Run 0005 BENNETT ROBERT 1,600.35 12.50 0016 LOCK ANDREW S 357.72 79.85 0080 PARKER JAMES E 18,200.00 165.00 0401 REDDING OLIVIA 16,123.99 2,301.75 1375 BENTON ALEX J 3,250.00 56.50 1442 ADAMS JUNE R 4,635.21 125.16 1842 COLE ROBERT N 14,285.14 6,385.29
CONTRIBUTION TO COMPUTER LANGUAGE COBOL programs are in use globally in governmental and military agencies, in commercial enterprises, and on operating systems such as IBM's z/OS, Microsoft's Windows, and the POSIX families
HOW WIDELY USED IS COBOL?? -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].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.