F452 Define Flashcards
Define what a serial file means.
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
Define what is meant by a random file
The address of each record is calculated from the key using a hash algorithm. The records may be contiguous.
Define what is meant by a function
A subroutine …
… which can return a single value
So it can be used within expressions (as a variable)
Define what is meant by a recursion.
When a function/procedure/subroutine calls itself
It has a stopping condition to tell it the recursion when to stop
Define what is meant by a sequence.
all instructions are executed…
… once
… in the order in which they appear
Define what is meant by selection.
a condition is used
to determine which of the statements (if any) will be executed
as a result some instructions may not be executed
Define what is meant by iteration.
a group of instructions is repeated
for a set number of times …
… or until a condition is met
Define what is meant by a validation.
Input data is checked by the computer
… against a set of rules
…to ensure that it is reasonable/sensible
Define what is meant by an array.
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.
Define what is meant by a variable.
An identifier/name
Associated with a particular memory location.
Used to store (and manipulate) data
…which can be changed while the program is running.
Define what is meant by a constant.
When a constant is declared it must be given a value.
The value cannot be changed while the program is running.
Define what is meant by a parameter.
(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
Define what is meant by a local variable
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)
Define what is meant by a global variable.
A global variable is declared at the beginning of a program
… and is available throughout the program
Define what is meant by beta-testing.
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
Define what is meant by acceptance-testing.
… 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.
Define what is meant by black box testing.
Different possible inputs are tested…
… to see if they produce the expected output
How the program works is not considered
Define what is meant by statement
A single instruction …
… which can be executed
suitable example
Some statements can contain others (eg IF, WHILE)
Define what is meant by white-box testing.
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.
Define what is meant by nesting.
Placing a construct within another construct and they are not allowed to overlap.
Define what is meant by procedure.
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
Define what is meant by a keyword violation error
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…)
Define what is meant by a syntax error
It breaks the rules of the language
Define what is meant by a run time error
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.
Define what is meant by a logic error
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
Define what is meant by an indexed sequential file.
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
Define what is meant by a recursive algorithm
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.
Define what is meant by a alpha testing
Testing is carried out by the programmers/software company playing the role of the user during development to find bugs in the program,.
Define what is meant by a identifier
A name given to a variable or a sub-routine.
Define what is meant by initialisation
Setting starting values of a variable before the variable is used in an expression.
Define what is meant by an integer
A whole number.
Define what is meant by operator precedence.
A default order in which operations in an expression are carried out.
Define what is meant by a 2-dimensional array.
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.
Define what is meant by stepwise refinement.
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.
Define what is meant by a top-down design.
Where the tasks that the program needs to perform are split into smaller sub-tasks.
Define what is meant by installation
When the program and files are copied/downloaded onto the device of where the program will be used.
Define what is meant by scope of a variable
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.
