History.
Developed by 1959 by a group called COnference on Data Systems Language (CODASYL). First COBOL compiler was released by December 1959.
First ANSI approved version – 1968
Modified ANSI approved version – 1974 (OS/VS COBOL)
Modified ANSI approved version – 1985 (VS COBOL 2)
This book is written based on IBM COBOL for OS/390 V2R2.
Speciality.
- First language developed for commercial application development, which can efficiently handle millions of data.
- Procedure Oriented Language - Problem is segmented into several tasks. Each task is written as a Paragraph in Procedure Division and executed in a logical sequence as mentioned.
- English Like language – Easy to learn, code and maintain.
Coding Sheet.
1 7 12 72 80
 |
1-6 Page/line numbers – Optional (automatically assigned by compiler)
7 Continuity (-), Comment (*), Starting a new page (/)
Debugging lines (D)
8-11 Column A –Division, Section, Paragraph, 01,77 declarations must begin here.
12-72 Column B –All the other declarations/statements begin here.
73-80 Identification field. It will be ignored by the compiler but visible in the source listing.
Language Structure.
Character | Digits (0-9), Alphabets (A-Z), Space (b), Special Characters (+ - * / ( ) = $ ; “ > < . ,) |
Word | One or more characters- User defined or Reserved |
Clause | One or more words. It specifies an attribute for an entry |
Statement | One or more valid words and clauses |
Sentence | One or more statements terminated by a period |
Paragraph | One or more sentences. |
Section | One or more paragraphs. |
Division | One or more sections or paragraphs |
Program | Made up of four divisions |
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