Data Structures and Algorithms

By default, Perl's sort function performs a standard ASCII-betical (lexicographical) comparison. When sorting the strings '100', '80', and '70', '100' comes first because its leading character '1' is ASCII-ordered before '7' and '8', yielding 100 70 80.

The delete function is specifically designed to remove a key-value pair from a hash (associative array). push/pop/shift/unshift are array operations that don't apply to hashes. delete is the correct and idiomatic way to remove hash elements.

push appends @sublist to the end of @array. splice(@array, scalar(@array), 0, @sublist) inserts @sublist at position equal to the array's length (the end), without removing any elements (0 elements removed).

COBOL SORT statement supports sorting on multiple keys using ASCENDING/DESCENDING KEY syntax with multiple field names separated by commas.

Oracle's default and most common indexing system is B-Tree (Balanced Tree) indexing. Bitmap indexing is an optional feature in Oracle used for low-cardinality columns, not the default. Functional indexing exists but is not a separate indexing system - it's just indexing on function results. Binary tree is not a standard Oracle indexing term.

In VBScript (used by QTP), UBound(array) returns the highest index of an array, which equals length minus one for zero-based arrays. LBound returns the lowest index, typically zero.

A Unique Secondary Index typically involves a two-AMP operation: one AMP to access the index subtable (which contains the PI value), then a second AMP to retrieve the base row using that PI value. However, if the index row and base row happen to reside on the same AMP, it becomes a single-AMP operation. The exact number depends on row location.

An Algorithm is a step-by-step sequential process that a computer follows to perform computations or solve problems. Logarithm is a mathematical function, Boolean Algebra deals with logical operations, and Syntax refers to language structure rules. Only Algorithm correctly describes a computational procedure.

Collections.reverseOrder() accepts a Comparator and returns a new Comparator that imposes the reverse ordering. When passed to Collections.sort(), it sorts the list in the opposite order of the original comparator. This is the standard way to reverse sort order in Java.

The <=> operator (spaceship operator) is Perl's numeric comparison operator, returning -1, 0, or 1. It's the standard way to sort numerically: sort { $a <=> $b } @array. The cmp operator is for string comparison, while < and > are simple comparison operators not typically used directly in sort.

The shift function removes and returns the first element of an array, shortening the array by one. It's commonly used to process array elements sequentially. unshift adds to the beginning, delete removes hash elements, and move is not a built-in Perl function.

When chomp is used on an array (@array), it operates on ALL elements, removing trailing newlines from each one. It doesn't just work on first or last element. This is a useful feature for cleaning up multiple lines at once. The option 'wont work on array' is incorrect.

ISAM stands for Indexed Sequential Access Method, which is a file organization method that allows both sequential and direct access to records using an index structure.