COBOL Programming Fundamentals

In COBOL, level numbers from 01 to 49 are used to define the hierarchical structure of data items, applicable to both group and elementary items. Level 01 represents the highest level (record definition), while 02-49 are used for subordinate group or elementary items. Option 00-49 is invalid because level 00 does not exist.

COBOL supports various data categories including numeric, alphabetic, alphanumeric, and numeric-edited fields, which are defined using different PICTURE clause symbols. Since all these options represent valid data types in COBOL, the correct selection is 'ALL'.

In COBOL, the JUSTIFIED clause can only be used with alphabetic (A) and alphanumeric (X) data types, not with numeric (edited or unedited) data types. Since it cannot be used with all data types, the answer is NO.

PERFORM and GOTO are both unconditional transfer statements in COBOL. PERFORM transfers control to a paragraph or section and automatically returns, while GOTO transfers control to the specified paragraph without any automatic return mechanism. Both statements execute regardless of any condition.

Index-names defined via the INDEXED BY clause represent binary displacement values managed internally by the compiler. Because they are not standard data items, standard COBOL prohibits displaying index-names directly with a DISPLAY statement, making the statement true.

For VSAM files, file labels are managed entirely by the operating system and VSAM services. The LABEL RECORDS clause in COBOL is syntax-checked for compatibility but has no operational effect on execution, making the statement true.

In COBOL, the CONFIGURATION SECTION is mandatory in the ENVIRONMENT DIVISION. It defines the computer and other configuration-related information for the program. While some entries within it may be optional in certain compilers, the section itself must be present in a valid COBOL program structure.

SEARCH ALL requires the table to be arranged in a specific order (ASCENDING or DESCENDING) as defined by the KEY clause. For predictable results, the key must uniquely identify each table entry. If duplicates exist, SEARCH ALL may return any matching entry, making the result unpredictable. This requirement is due to the binary search algorithm used.

For REWRITE to work successfully, the file must be opened in I-O mode. INPUT mode only allows reading, OUTPUT mode is for creating new files, and I-O mode allows both reading and updating existing records. REWRITE modifies an existing record, so it requires the update capability provided by I-O mode.

An EVALUATE statement with no WHEN phrases is syntactically valid in COBOL. Such a construct effectively does nothing but is legal syntax. The EVALUATE clause can have subjects (A ALSO B) and then immediately end without any conditional branches, which compiles without error.

Special registers in COBOL are predefined reserved words that provide runtime information. PSW (Program Status Word) contains condition codes, PC (Program Counter) is not a standard COBOL special register but may appear in system-specific implementations, and SP (Stack Pointer) may be available in certain environments. PR is not a recognized special register. Note: PC and SP are more commonly associated with assembly language than standard COBOL.

Using NEXT SENTENCE in COBOL transfers program control to the statement immediately following the next period. Since the period is placed after ADD +1 TO INPUT-COUNT., executing NEXT SENTENCE skips the addition step entirely, leaving INPUT-COUNT unchanged.

When defining ASCENDING or DESCENDING KEY for table sorting or searching with SEARCH ALL, the key data items must be comparable and have a total ordering. Floating-point numbers should not be used as keys because they can have representation issues (like NaN, infinity, or precision problems) that make sorting and binary search unreliable and unpredictable.

REWRITE updates existing records in a file, requiring both read and write access. I-O mode permits reading a record, modifying it, and writing it back to the same position. I or O modes alone are insufficient for REWRITE operations.

EJECT is a COBOL compiler directing verb that advances the compiler listing to a new page. It helps organize printed source code listings for better readability.

BLANK WHEN ZERO clause has specific restrictions in COBOL. Level 66 is RENAMES (renaming clause), level 88 is condition names (not actual data fields), and signed fields have special storage requirements that don't allow blanking.