[PL] PRELIM ANSWERS

Some primitive data types are merely reflections of the _____.

hardware

Arrays are homogeneous aggregates of data elements identified by their position relative to the ______.

first element

*Associative arrays are unordered collections of data elements indexed by ______.

keys

A ______ defines a collection of data objects and a set of predefined operations on those objects.

data type

Java’s signed integer sizes include ______, short, int, long.

byte

_______ data types are essential for business applications like money handling.

decimal

______ data types are data types not defined in terms of other data types.

Primitive data types

Character types are often stored as ______.

numeric codings

An ______ is an ordinal type whose possible values are named constants.

enumeration

*Arrays allocated during run-time are located in either ______, ______, or ______.

heap, stack, global/static memory

A ______ is a multi-dimensional array in which all of the rows have the same number of elements and all columns have the same number of elements, while a ______ has rows with varying numbers of elements.

rectangular array, jagged array

A ______ is a possibly heterogeneous aggregate of data elements in which the individual elements are identified by names.

record

Extended BNF (EBNF) uses brackets [ ], parentheses ( ), and braces { } to represent ______, ______, and ______ respectively.

optional parts, alternative parts, repetitions

A grammar is ambiguous if and only if it generates a ______ that has two or more distinct ______.

sentential form, parse trees

A derivation is a repeated application of rules, starting with the ______ and ending with a sentence.

start symbol

In BNF, abstractions act like syntactic variables, also called ______.

nonterminal symbols/nonterminals

______ refers to the form or structure of the expressions, statements, and program units.

syntax

______ refers to the meaning of the expressions, statements, and program units.

semantics

Name two users of a language definition.

implementers, programmers

______ variables are a special category of nonlocal variables.

global

In dynamic scoping, the referencing environment includes local variables and all visible variables in ______ subprograms.

active

______ is an association between an entity and an attribute, such as between a variable and its type or value.

binding

The ______ of a variable is the time during which it is bound to a particular memory cell.

lifetime

List the six attributes that characterize a variable.

name, address, type, value, lifetime, scope

Enumerate five possible binding times in programming languages.

Language Design Time

Language Implementation Time

Compile Time

Load Time

Runtime

If two variable names can be used to access the same memory location, then those two variable names are called ______.

aliases

A binding is ______ if it first occurs before run time and remains unchanged throughout program execution.

static

What are the two fundamental pointer operations?

assignment & dereferencing

What is a dangling pointer?

A pointer points to a heap-dynamic variable that has been deallocated

A ______ is a type whose range of values consists of memory addresses and a special value, ______.

pointer type, null