CUCO flashcards

36 cards. Read the term and the definition here. The deck at the top of this page is optional.

Four divisions of COBOL

IDENTIFICATION, ENVIRONMENT, DATA, PROCEDURE - in that order. Only IDENTIFICATION is technically required by the standard, but a runnable program needs all four.

Area A and Area B

Fixed-format source areas: columns 8-11 (Area A) hold division, section, paragraph names and 01/77 levels; columns 12-72 (Area B) hold statements and other level numbers.

Comment indicator column 7

In fixed format, an asterisk in column 7 marks a comment line, a slash causes a page eject, a hyphen continues the previous line, and D marks a debugging line.

Figurative constants

Reserved words representing literal values: ZERO, SPACE, HIGH-VALUE, LOW-VALUE, QUOTE, NULL. ALL literal repeats a literal to fill the receiving item.

Period and scope

A period ends a sentence and terminates the scope of all open IF, PERFORM, and EVALUATE statements. A misplaced period silently changes control flow.

COBOL word rules

A user-defined word may contain letters, digits, and hyphens, must contain at least one letter, cannot start or end with a hyphen, and cannot be a reserved word.

LOCAL-STORAGE vs WORKING-STORAGE

WORKING-STORAGE is allocated and initialized once per run unit; LOCAL-STORAGE is allocated and initialized on every invocation of the program or subprogram.

PICTURE S and V

S declares a sign and V an implied decimal point; neither occupies a character position. PIC S9(3)V99 occupies 5 bytes in DISPLAY usage.

COMP-3 byte size formula

Packed decimal size in bytes equals INT((digits + 1) / 2) rounded up, where the +1 accounts for the sign nibble. PIC S9(5) COMP-3 is 3 bytes.

Level 88 condition-name

A level 88 attaches a condition-name to a data item with VALUES ARE ... THRU ... ranges. SET condition-name TO TRUE moves the associated value into the item.

REDEFINES rules

REDEFINES must immediately follow the redefined item at the same level, cannot change the item's size in a file record, and does not initialize storage.

Group item usage

A group item has no PICTURE and no USAGE clause. Its usage is DISPLAY unless all subordinate elementary items share a usage, and moves into it are alphanumeric.

Level 66 RENAMES

Level 66 regroups previously defined elementary items in the same record. It cannot overlap other 66 entries and cannot rename an item containing an OCCURS.

PERFORM WITH TEST AFTER

PERFORM ... UNTIL tests before execution and may run zero times; WITH TEST AFTER tests after each execution and guarantees at least one execution.

EVALUATE TRUE

EVALUATE TRUE evaluates each WHEN as a condition rather than comparing values, making it the standard replacement for nested IF/ELSE chains.

GO TO DEPENDING ON

Branches to the nth procedure named in the statement, where n is the value of the identifier. Values outside 1 through n cause no branch.

CALL BY REFERENCE vs CONTENT

BY REFERENCE (the default) passes a pointer to the caller's item; BY CONTENT passes a copy the subprogram cannot use to change the caller's data.

INITIAL clause

The INITIAL clause on a subprogram resets WORKING-STORAGE and internal state on every CALL. Without it, WORKING-STORAGE retains values between calls.

NEXT SENTENCE vs CONTINUE

CONTINUE is a no-op statement. NEXT SENTENCE jumps to the next period, which differs from CONTINUE when inline scope terminators such as END-IF are used.

File OPEN modes

OPEN INPUT reads; OUTPUT creates or overwrites; EXTEND appends; I-O allows read, rewrite, and delete. REWRITE and DELETE require the file opened I-O.

FILE STATUS codes

Two-character status: 00 success, 10 end of file, 22 duplicate key, 23 record not found, 35 file not found on OPEN.

DYNAMIC access mode

DYNAMIC allows both sequential and random access on the same file in one run. It requires a RECORD KEY or RELATIVE KEY in the SELECT statement.

START statement

START positions an indexed or relative file at a key value. The following READ NEXT retrieves records from that position onward.

OCCURS and INDEXED BY

OCCURS n TIMES defines a table with 1-relative subscripts. INDEXED BY creates an index usable only with SET, SEARCH, and relative subscripting.

SEARCH ALL requirements

SEARCH ALL performs a binary search and requires the table to be sorted ascending or descending on the key, with the key as the first or only item.

OCCURS DEPENDING ON

ODO makes a table variable length. The ODO object must be an integer defined before the table, and the table must be last in a file record.

Nested OCCURS subscripts

A nested table requires one subscript per dimension, listed outermost first. T(I,J) is defined by OCCURS at level 05 followed by OCCURS at level 10.

RECURSIVE clause

The RECURSIVE clause permits a subprogram to call itself. LOCAL-STORAGE is then allocated per invocation, keeping each recursion level independent.

S0C7 abend

A data exception caused by nonnumeric data in a numeric field, often from an uninitialized COMP-3 item or a bad move into a packed field.

S0C4 abend

A protection exception caused by an invalid address, typically a bad CALL USING parameter, an out-of-range subscript, or a mismatched LINKAGE SECTION.

WITH DEBUGGING MODE

When debugging mode is active, lines with D in column 7 are compiled. The DEBUG-ITEM special register exposes the last debug line processed.

COPY statement

COPY inserts copybook source at compile time. Changing a copybook requires recompiling every program that copies it, a common maintenance defect.

JSON GENERATE and PARSE

COBOL 2014 statements that convert between COBOL data structures and JSON text, complementing XML GENERATE and XML PARSE for web integration.

GnuCOBOL

An open-source COBOL compiler supporting most COBOL 85 and many 2002+ features. It translates COBOL to C and runs on Linux, Windows, and containers.

Object-oriented COBOL

COBOL 2002 introduced CLASS-ID and METHOD-ID for object-oriented programming, along with user-defined functions and free-format source.

EXEC CICS END-EXEC

Embedded transaction commands in the PROCEDURE DIVISION used to run COBOL programs under CICS on z/OS, delimited by EXEC CICS and END-EXEC.