CS Key Terms

Question 1

Iteration

Answer 1

A block of code is executed repeatedly, either until a condition is met or for a set number of times.

Question 2

Statement

Answer 2

Any individual step/instruction in the code

Question 3

Assignment

Answer 3

Assignment is used to set the value of a variable, e.g. x := 5; (Usually described as X becomes equal to 5). The variable is written on the left and the value on the right. Do not confuse this with the equalities operator seen below.

Question 4

Serial files

Answer 4

Data is stored in the file in the order in which it was entered. New data is appended to the end of the file.

Question 5

Sequential files

Answer 5

The data is sorted according to a key field. New data is inserted in the correct position.

Question 6

Watches/variable checks

Answer 6

Outputting the value of variables at specified points in the program, or when they change.

Question 7

Translator diagnostics

Answer 7

Messages generated by the translator when converting the code to executable code. Helpful in finding syntax errors and some logic errors. Sometimes the line the error is reported on is not accurate.

Question 8

Logic error

Answer 8

The code as it is written does something which is different from what the programmer intended. Usually detected while testing, as the program produces an incorrect result.

Question 9

String

Answer 9

Textual data in the form of a list of characters, for example words and punctuation. String data is made up of character data and will usually vary in length.

Question 10

Sequence

Answer 10

Executes each statement once, in the order in which it is given.

Question 11

Subroutines

Answer 11

A sub-program, a set of statements written to perform a given task as part of solving the main problem. It can be called using its identifier.

Question 12

Function

Answer 12

Specifically a subroutine which returns a single value and can therefore be used as if it were a variable.

Question 13

Parameter/argument

Answer 13

Data item being supplied to a function or procedure when it is called

Question 14

Pseudo code

Answer 14

A method of writing an algorithm using normal language which will mimic the programming code, but without worrying about specific syntax. It is useful for planning programs or explaining them to other people.

Question 15

Indentation

Answer 15

Every time a new line of code is placed within a programming construct, e.g. If statement, the code should be intended to show that it exists within that structure. This makes it clear where each structure starts and finishes.

Question 16

Initialising variables

Answer 16

This means giving variables a starting value, to ensure it starts at the right value or doesn’t hold a junk value from memory. Typically 0, “” or false, although could be a more specific value depending on the program.

Question 17

Syntax error

Answer 17

The statement in the code does not follow the rules of the language. Usually detected by the translator, as the statement cannot be understood and translated.

Question 18

Run-time error

Answer 18

The program attempts an impossible operation (such as division by zero, accessing a missing file, etc.). Usually detected while testing, as the program crashes.

Question 19

Stepping

Answer 19

Executing the code a line at a time after a break point has been specified. Useful to check variables and see what individual lines of code are doing to locate logical errors.

Question 20

Dry run

Answer 20

The programmer goes through the code line by line as the computer would, often using a trace table to keep track of variables to check that the code performs as expected.

Question 21

Break points

Answer 21

Causing the program to halt at a specified marker. The programmer can then check the values of variables, and step through the code (execute the code one line at a time).

Question 22

Reserved words

Answer 22

Words which are reserved for a specific purpose in the programming language, e.g. IF… WHILE… DO…

Question 23

Commenting

Answer 23

Explaining a section of code with normal language in order to make it more understandable for other people. Comments should be made when the code is written and not after it has been written.

Question 24

Procedure

Answer 24

A subroutine which performs a task, but has no return value

Question 25

Transparency

Answer 25

Transparency in code is achieved by giving variables, constants, functions and procedures suitable names. This makes it easier for someone else to read the code and understand the purpose of those features.

Question 26

Boolean

Answer 26

Can only hold two possible values e.g. True or False, Yes or No

Question 27

Variable

Answer 27

The identifier associated with a particular memory location used to store data. By using a variable you can store, manipulate and retrieve data without knowing what the data will be, e.g. var x := integer

Question 28

Time

Answer 28

Used to store only real Times e.g. 12:42 but not 25:61

Question 29

Date

Answer 29

Used to store only real Dates e.g. 20/01/2010 but not 32/14/2011

Question 30

Char

Answer 30

Any single character represented by the codes from the character set in use on the computer.

Question 31

Integer

Answer 31

Any whole number, negative or positive e.g. 1, 34, 234564, -14 (there is a maximum value for each computer)

Question 32

Equality

Answer 32

Used to check whether two values are equal e.g. x = 5 (Described as x is equal to 5). This would usually be seen as a condition in an IF statement or the end condition of a loop.

Question 33

Array

Answer 33

An array contains several items of data, of the same type, grouped under one identifier. Each item in the array (element) has an index which allows that specific element to be access.

Question 34

Recursion

Answer 34

Recursion is when a subroutine (a procedure or a function) calls itself. The recursive subroutine is executed as normal until it gets to the line where it calls itself. At this point the subroutine is paused and a new call to the same subroutine is started. This will continue until an end condition is reached or the computer runs out of memory.

Question 35

Nesting

Answer 35

Placing one or more programming constructs inside another.

Question 36

Identifier

Answer 36

The specific name of a variable, procedure or function within a program

Question 37

Selection

Answer 37

A comparison determines whether a block of code will be executed or not. Examples: if statement, case/switch statements

Question 38

Constant

Answer 38

A data item with a fixed value. It cannot be changed when the program is executed, e.g. const pi := 3.1416

Question 39

Real

Answer 39

Any number represented with a fractional part, e.g. 3.1416, -123.34