Chapter 9

Question 1

Two fundamental abstraction facilities can be included in a programming language, they are?

Answer 1

1) process abstraction

2) data abstraction

Question 2

Sub programs have what three characteristics?

Answer 2

1) Each subprogram has a single entry point
2) The calling program unit is suspended during the execution of the called subprogram, which implies that there is only one subprogram in execution at any given time
3) Control always returns to the caller when the subprogram execution terminates

Question 3

A sub program ___ describes the interface to and the actions of the subprogram abstraction.

Answer 3

definition

Question 4

A subprogram ___ is the explicit request that a specific subprogram be executed.

Answer 4

call

Question 5

A subprogram is said to be ___ if after having been called, it has begun execution but has not yet completed that execution.

Answer 5

active

Question 6

What are the two fundamental kinds of subprograms?

Answer 6

procedures, functions

Question 7

A subprogram ___, is the first part of the definitions and serves several purposes.

Answer 7

header

Question 8

What are the purposes of the subprogram header (3)?

Answer 8

1) Specifies that the following syntactic unit is a subprogram definition of some particular kind
2) If the subprogram is not anonymous, provides a name for the program
3) May specify a list of parameters

Question 9

The ___ ____ of a subprogram contains the number, order, and types of its formal parameters.

Answer 9

parameter profile

Question 10

The ___ of a subprogram is its parameter profile plus, if it is a function, its return type.

Answer 10

protocol

Question 11

Function declarations are common in C & C++ programs, where they are called ___. Such declarations are often placed in header files.

Answer 11

prototypes

Question 12

The parameters in the subprogram header are called ___ parameters.

Answer 12

formal

Question 13

Subprogram call statements must include the name of the subprogram and a list of parameters to be bound to the formal parameters of the subprogram; these parameters are called ___ parameters.

Answer 13

actual

Question 14

an effective and safe method of relating actual parameters to their corresponding formal parameters, are called ___ parameters

Answer 14

positional

Question 15

When a parameter lists is long, ___ parameters, in which the name of the formal parameter to which an actual parameter is to be bound is specified with the actual parameter in a call.

Answer 15

keyword

Question 16

____ are collections of statements that define parameterized computations.

Answer 16

subprograms

Question 17

What is the difference between a function and procedure subprogram?

Answer 17

functions return values and procedures do not

Question 18

What are the two methods in which a procedure can produce a result?

Answer 18

1) Changes a variable that is not part of the formal parameters but is visible by the procedure and calling unit (e.g. global variable)
2) procedure has formal parameters that allow the transfer of data to the caller (e.g. an array)

Question 19

Design issues associated with subprograms (11).

Answer 19

1) Are local variables statically or dynamically allocated?
2) Can subprogram definitions appear in other subprogram definitions
3) Are the types of the actual parameters checked against the types of the formal parameters
4) If subprograms can be passed as parameters and subprograms can be nested, what is the referencing environment of passed subprogram?
5) Are function side effects allowed?
6) What types of values can be returned from function?
7) How many values can be returned from functions?
8) Can subprograms be overloaded?
9) Can subprograms be generic?
10) If the language allows nested subprograms. are closures supported?
11) What parameter-passing emthod or methods are used?

Question 20

Variables that are defined inside subprograms are called ___ variables, because their scope is usually the body of the subprogram in which they are defined.

Answer 20

local

Question 21

Formal parameters are characterized by what three distinct semantics models?

Answer 21

1) They can receive data - in mode
2) They can transmit data - out-mode
3) They can do both - inout mode

Question 22

When a parameter is ___ by ___, the value of the actual parameter is used to initialize the corresponding formal parameter, which then acts as a local variable in the subprogram, thus implementing in-mode semantics.

Answer 22

pass by value

Question 23

__ by __ is an implementation model for out-mode parameters where no value is transmitted to the subprogram; the corresponding formal parameter acts as a local variable, but just before control is transferred back to the caller, its value is transmitted back to the caller’s actual parameter.

Answer 23

pass by result

Question 24

__-__-___-__ is an implementation model for inout-mode parameters in which actual values are copied

Answer 24

pass-by-value-result

Question 25

Pass-by-value-result is sometimes called __- by-___, because the parameters ___ to the formal parameter at subprogram entry and then ___ back at subprogram termination

Answer 25

pass-by-copy, copied, copied

Question 26

__-by-___ is a second implementation model for inout-mode parameters which transmits an access path, such as a pointer, to the called subprogram.

Answer 26

Pass-by-reference

Question 27

__-by-___ is an inout-mode parameter transmission method that does not correspond to a single implementation model. This is where the actual parameter is, in effect, textually substituted for the corresponding formal parameter in all its occurrences in the subprogram.

Answer 27

Pass-by-name

Question 28

In most contemporary languages, parameter communication takes place through the ___-___ ___.

Answer 28

run-time stack

Question 29

The run-time ___ is initialized and maintained by the run-time ___, which manages the execution of programs.

Answer 29

stack, system

Question 30

The run-time ___ is used extensively for subprogram control linkage and parameter passing.

Answer 30

stack