Deck 7: Basic Semantics

Question 1

Locations are places where values can be stored.

Answer 1

True

Question 2

A translator's symbol table stores the mappings between names and attributes.

Answer 2

True

Question 3

The declaration before use scoping rule in C allows any declaration to be used as long as it is declared within the current block.

Answer 3

False

Question 4

Names can be bound to attributes prior to translation time,as in the case of predefined identifiers.

Question 5

Each function call generates a region of allocated memory associated with the function; this is called an activation record.

Question 6

If an operator can be used to perform more than one operation,it is said to be shadowed.

Question 7

In C,blocks are called compound statements.

Question 8

Any scoping structure that can be referenced directly in a language must have its own symbol table.

Question 9

Declaration visibility includes only those regions of a program where the bindings of the declaration apply.

Question 10

When a nonlocal name is used in an expression,the declaration that applies to that name cannot be determined until execution time under dynamic scoping.

Question 11

A block consists of a sequence of declarations followed by a sequence of statements.

Question 12

In C++,declarations that bind all potential attributes are called prototypes.

Question 13

The lifetime of an object is the duration of its allocation in the environment.

Question 14

Declarations in surrounding blocks are called nonlocal declarations.

Question 15

A fundamental abstraction mechanism in any programming language is the use of names,or identifiers to denote language entities or constructs.

Question 16

The meaning of a name cannot be determined by the attributes associated with it.

Question 17

Binding time refers to when an attribute is computed and bound to a name.

Question 18

Static binding occurs during execution.

Question 19

Names can be reused within nested blocks by associating each declaration with a level number and an offset.

Question 20

Lexical scoping rules are sometimes called dynamic scoping.

Question 21

____ are generally bound at load time.

A) Global variables
B) Predefined identifiers
C) All variables
D) All attributes

Question 22

The bindings of ____ to storage locations is called the memory.

A) names
B) values
C) attributes
D) identifiers

Question 23

____ are any storable quantities,such as integers.

A) Data
B) Values
C) Locations
D) Identifiers

Question 24

The bindings of names to storage locations is called the ____.

A) translator
B) compiler
C) environment
D) symbol table

Question 25

In a block-structured language with heap allocation,there are three kinds of allocation: static (for global variables),automatic (for local variables),and dynamic (for heap allocation).

Question 26

The ____ is the level number and offset of a declared name.

A) lexical address
B) block address
C) compound address
D) explicit address

Question 27

____ binding occurs during execution.

A) Static
B) Rapid
C) Value
D) Dynamic

Question 28

The body of an externally defined function will not be bound until ____.

A) execution time
B) link time
C) translation time
D) load time

Question 29

If an operator performs more than one function it is said to be ____.

A) overloaded
B) shadowed
C) implicit
D) variable

Question 30

The scope of a binding is ____.

A) the region over which the binding is maintained
B) the precision of the binding
C) the time when the binding takes place
D) the magnitude of the binding

Question 31

Static constants are always computed at load time.

Question 32

In C++,declarations that bind all potential attributes are called ____.

A) prototypes
B) definitions
C) symbols
D) explicits

Question 33

Each call to a method is referred to as a(n)____.

A) invocation
B) execution
C) activation
D) branching

Question 34

In object-oriented languages such as Java and Smalltalk,the ____ is the only declaration that does not itself need to be inside another class declaration.

A) class
B) module
C) file
D) package

Question 35

____ declarations are associated with a specific block.

A) Global
B) Specific
C) Local
D) General

Question 36

Dangling references are locations that have been deallocated from the environment but can still be accessed by a program.

Question 37

Java requires manual deallocation of objects.

Question 38

Java uses assignment by cloning for all object variables.

Question 39

In C,the scope of a binding is limited to the block in which its associated declaration appears.This scoping rule is called ____ scope.

A) block
B) lexical
C) package
D) namespace

Question 40

A variable declared locally within a block is said to ____ a global variable of the same name.

A) occlude
B) override
C) mirror
D) shadow

Question 41

When a change in the value of a variable persists beyond the execution of a statement,a(n)____ has occurred.

A) side effect
B) persistent effect
C) error
D) compound change

Question 42

A ____ is an object whose stored value can change during execution.

A) variable
B) class
C) pointer
D) method

Question 43

Language systems that automatically reclaim garbage are said to perform ____.

A) memory reallocation
B) memory reclamation
C) recycling
D) garbage collection

Question 44

Dynamic allocation places variables ____.

A) on the stack
B) in the symbol table
C) in the pointer list
D) on the heap

Question 45

A pointer is an object whose stored value is a(n)____.

A) compound value
B) activation record
C) reference to another object
D) direction

Question 46

A(n)____ occurs when the same object is bound to two different names at the same time.

A) conflict
B) alias
C) multi-reference
D) duplicate

Question 47

Garbage is defined as ____.

A) a collection of unused constants
B) a collection of unused variables
C) variables with duplicate values
D) memory that has been allocated in the environment but that has become inaccessible to the program

Question 48

In C,the ____ operator retrieves the address of a variable as a pointer.

A) dereference
B) reference
C) address of
D) allocation

Question 49

A ____ constant is a name for a literal.

A) compile-time
B) static
C) manifest
D) symbolic

Question 50

Assignment by sharing works by ____.

A) copying the value to a new location
B) duplicating memory addresses
C) copying the location of the first variable to the second
D) accessing shared memory