F452 Define

Question 1

Define what a serial file means.

Answer 1

The data is stored chronologically/in the order in which it is entered
New data always appended / added to the end of the file
You need to read each preceding item to reach an item you are searching for

Question 2

Define what is meant by a random file

Answer 2

The address of each record is calculated from the key using a hash algorithm. The records may be contiguous.

Question 3

Define what is meant by a function

Answer 3

A subroutine …
… which can return a single value
So it can be used within expressions (as a variable)

Question 4

Define what is meant by a recursion.

Answer 4

When a function/procedure/subroutine calls itself

It has a stopping condition to tell it the recursion when to stop

Question 5

Define what is meant by a sequence.

Answer 5

all instructions are executed…
… once
… in the order in which they appear

Question 6

Define what is meant by selection.

Answer 6

a condition is used
to determine which of the statements (if any) will be executed
as a result some instructions may not be executed

Question 7

Define what is meant by iteration.

Answer 7

a group of instructions is repeated
for a set number of times …
… or until a condition is met

Question 8

Define what is meant by a validation.

Answer 8

Input data is checked by the computer
… against a set of rules
…to ensure that it is reasonable/sensible

Question 9

Define what is meant by an array.

Answer 9

A data structure / set of data items
Of the same data type
Grouped under one identifier
Each item can be addressed using its index/subscript.

Question 10

Define what is meant by a variable.

Answer 10

An identifier/name
Associated with a particular memory location.
Used to store (and manipulate) data
…which can be changed while the program is running.

Question 11

Define what is meant by a constant.

Answer 11

When a constant is declared it must be given a value.

The value cannot be changed while the program is running.

Question 12

Define what is meant by a parameter.

Answer 12

(A variable) which holds an item of data…
… which is supplied/passed to a subroutine/procedure/function
It is given an identifier when the subroutine is defined
It is substituted by an actual

Question 13

Define what is meant by a local variable

Answer 13

A local variable is declared within a subprogram/ procedure/function/block of code
… and is only available within that section of code
… and is destroyed/deleted when the subprogram exits
A local variable can override a global variable (with the same name)

Question 14

Define what is meant by a global variable.

Answer 14

A global variable is declared at the beginning of a program

… and is available throughout the program

Question 15

Define what is meant by beta-testing.

Answer 15

In beta-testing…
… the nearly complete program…
… is given to a group of users to test/is tested under normal operating conditions/tested by people who were not involved in the production
The aim is to find any bugs which the programmer has overlooked

Question 16

Define what is meant by acceptance-testing.

Answer 16

… the program is considered complete
The programmer demonstrates the working program to the client
The aim is to show that the program meets all the requirements of the client.

Question 17

Define what is meant by black box testing.

Answer 17

Different possible inputs are tested…
… to see if they produce the expected output
How the program works is not considered

Question 18

Define what is meant by statement

Answer 18

A single instruction …
… which can be executed
suitable example
Some statements can contain others (eg IF, WHILE)

Question 19

Define what is meant by white-box testing.

Answer 19

In white box testing the actual steps of the algorithm are tested to make sure all parts work as intended. You need to test all possible paths through the algorithm.

Question 20

Define what is meant by nesting.

Answer 20

Placing a construct within another construct and they are not allowed to overlap.

Question 21

Define what is meant by procedure.

Answer 21

A subroutine/subprogram / Section of code which is given an
identifier
It can be called from the main program / from another
procedure
When called the code in the procedure is executed
And then control is passed back to where the procedure is
called from

Question 22

Define what is meant by a keyword violation error

Answer 22

Words which are already used for a purpose within the
Language
A reserved word/ cannot be used as an identifier (for a
variable, subroutine etc…)

Question 23

Define what is meant by a syntax error

Answer 23

It breaks the rules of the language

Question 24

Define what is meant by a run time error

Answer 24

A statement in a code that cannot be executed due to effects not catered for by the program. It is detected when the program crashes.

Question 25

Define what is meant by a logic error

Answer 25

Code can be compiled or executed/follows the rules of the language but does not perform the intended action. E.g. using wrong mathematical operation

Question 26

Define what is meant by an indexed sequential file.

Answer 26

Records are arranged in order of a primary key. An indexed is kept which is used to jump to groups or blocks of records. e.g. red colour for first 5 records, yellow for next 5 etc. the index must be in the same order as the records

Question 27

Define what is meant by a recursive algorithm

Answer 27

An algorithm which calls itself with smaller input values. Which obtains the results for the current input by applying simple operations to the returned value for the smaller input.

Question 28

Define what is meant by a alpha testing

Answer 28

Testing is carried out by the programmers/software company playing the role of the user during development to find bugs in the program,.

Question 29

Define what is meant by a identifier

Answer 29

A name given to a variable or a sub-routine.

Question 30

Define what is meant by initialisation

Answer 30

Setting starting values of a variable before the variable is used in an expression.

Question 31

Define what is meant by an integer

Answer 31

A whole number.

Question 32

Define what is meant by operator precedence.

Answer 32

A default order in which operations in an expression are carried out.

Question 33

Define what is meant by a 2-dimensional array.

Answer 33

A collection of data items of the same data type under one identifier. Uses 2 index numbers and can be represented as a grid with rows and columns.

Question 34

Define what is meant by stepwise refinement.

Answer 34

The overall problem is defined in a simple terms and then split into a number of smaller tasks. Each of these tasks is successively split and refined until they are small enough to be understood and programmed.

Question 35

Define what is meant by a top-down design.

Answer 35

Where the tasks that the program needs to perform are split into smaller sub-tasks.

Question 36

Define what is meant by installation

Answer 36

When the program and files are copied/downloaded onto the device of where the program will be used.

Question 37

Define what is meant by scope of a variable

Answer 37

The part of the program where a variable is available e.g. local or global. Global variable available throughout program. Local variable only applies to a sub-routine. If Global and Local use the same identifier/name then local variable takes precedence.