Previous Topic Next topic Print topic


Glossary

A

application program

A program used to perform a particular data processing task such as inventory control or payroll.

argument

A value passed to an invoked function, procedure, or program.

arithmetic operation

An operation such as addition, subtraction, multiplication, or division that is performed only on numeric fields.

array

An ordered set of values, all having the same data type.

array element

A data item in an array.

array index

The actual number of an element in an array, or the field containing the number or relative position of an element in an array.

attribute

Characteristics the compiler uses to interpret and store the data in a program.

B

based variable

A variable that does not have a block of storage of its own, or an address. Serves as a description of the storage, but a pointer value must be used to supply the address of the storage.

binary

Relating to, being, or belonging to a numbering system with a base of 2. Valid digits are 0 and 1.

binary format

Representation of a decimal value in which each field must be 2 or 4 bytes long. The sign (4. or –) is the leftmost bit of the field and the integer value is in the remaining bits of the field. Positive numbers have a zero in the sign bit and are in two's complement form.

bit string

A sequence of bits.

branching

The technique of bypassing specific instructions or operations to alter the sequential execution of instructions in a program.

by reference

An invoked procedure for a parameter uses the same memory location as the invoking procedure for the corresponding argument.

byte

A group of eight adjacent binary digits that represents one ASCII character.

by value

An argument is copied to a temporary block of storage in the calling routine's stack frame. The parameter is a description of the temporary storage.

C

called program

A program whose execution is requested by another program, a calling program.

calling program

A program that controls the execution of another program, a called program.

comment

Words or statements in a program, command, or file that serve as documentation instead of as instructions.

compilation

Translation of a source program into an executable program.

compiler

A program that translates a source program into an executable program.

compound statement

A statement that includes another statement.

constant

Data that has an unchanging, predefined value to be used in processing. A constant does not change during the execution of a program.

controlled variable

A variable whose storage is dynamically allocated and freed in generations. Controlled variables are allocated oniy when specified in an ALLOCATE statement.

D

data format

Controls the transmission and conversion of a value to or from a stream file.

data set

A collection of data external to a program.

data structure

An area in storage that is composed of one or more subfields. A data structure can be either program described or externally described.

declared name

A name used to denote an object operated upon by the program such as a variable, file, or label.

dynamic

Occurring at execution time.

E

execution

The carrying out of the instructions of a computer program by a processing unit.

expression

Consists of operands and operators.

extent

The range indicated by the bounds of an array dimension (the upper bound minus the lower bound plus 1) and the declared length of a string variable.

external procedure

A procedure not contained within another procedure.

F

factored declarations

Declare statements that contain parenthesized lists of names.

field

An area that is reserved and used for a particular item of information.

file

A named representation of a data set.

file constant

A pointer to, or designator of, a file control block.

file control block

A block of static storage in which information about the current status of a file is retained while the file is opened.

file value

Designates a file control block.

file variable

A variable that can be assigned file values.

format list

A list of format items that controls the transmission of data to or from a stream I/O file.

H

hexadecimal

Pertaining to a numbering system with a base of 16. Valid numbers are the digits 0 through 9 and the characters A through F, where A represents 10 and F represents 15.

I

internal procedure

A procedure nested within another procedure.

K

key

A value which is used to identify a record during an I/O operation.

keyword

A name used to denote part of a statement, such as a verb, option, or clause.

L

label

A symbolic name that represents a specific location in a program. A label can serve as the destination point for one or more branching operations.

M

major structure

A structure that is not a substructure.

members

Immediate components of a structure.

N

name

A single letter, or a sequence of letters, digits, and the underscore character. Also referred to as an identifier.

null pointer value

Unique value that does not address any variable. Indicates a pointer variable and does not address anything.

null string

A string of zero length.

O

ON-unit

A block of statements that are executed if a specifiedcondition occurs.

operand

A constant, a variable reference, a built-in function reference, or an expression.

operation

A defined action performed on one or more data items, such as adding, multiplying, comparing, or moving information.

P

parameter

A name that an invoked function, procedure, or program uses to refer to an argument.

picture

A string of symbols that defines the character occupying the corresponding space.

pictured value

Character-string values that represent fixed-point decimal numbers.

pointer value

The address of a variable's storage.

precision

The number of digits in an arithmetic value.

procedure

A sequence of statements, beginning with a PROCEDURE statement and ending with an END statement. Also referred to as a block.

program

A set of instructions that directs the computer to perform a series of tasks in a specified order. Consists of one or more external procedures.

R

record

A copy of a scalar, structure, or array variable.

record file

A sequence of discrete records that are either accessible sequentially or by character-string valued keys.

reference

A name together with any subscripts, pointer qualifier, or structure names necessary to indicate the purpose of the reference.

S

scalar variable

A variable that can have only a single value.

scope

The distinct region of the program text in which a name can be referenced.

self-defining structure

A BASED structure that contains information about its own fields. The value of one member is used to determine the amount of storage space allocated for another member of the same structure.

separator

A character or series of characters used to separate names, constants, numbers, and character strings.

sequential file

A file into which records are entered one after the other. If the file is keyed, the records are processed in the sequence of the access path.

simple reference

A name without any subscripts, pointer qualifier, or structure names.

stack frame

A block of storage allocated on a stack.

statement

A sequence of tokens ending with a semicolon. Except for assignment statements, all statements start with a keyword.

statement label

A name followed by a colon (:) that prefixes a statement.

stream file

A sequence of characters organized into lines and pages.

structure

A hierarchically ordered set of values that may be of different data types.

structure qualified reference

A sequence of names written left-to-right in order of increasing level numbers.

subscript

An integer valued expression used to reference an element of an array.

subscripted reference

A name that has been declared as an array, followed by a parenthesized list of subscript expressions.

substructure

A structure that is itself a member of another structure.

T

token

A name, constant, punctuation symbol, comment, or compile-time text modification statement.

V

variable

A name to which a value can be assigned during the execution of a program. A variable can only take on values of the type specified in its variable declaration.

Previous Topic Next topic Print topic