IGCSE Computer Science Paper 2 Definitions Worksheet: 7b Decomposition and Sub-systems and 7c Pseudocode and Flowcharts (Modules 136–145)
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Key terms
Write what each term means, in your own words.
1
CALL
2
PROCEDURE
3
abstract, decompose, draw, write
4
full-mark answer
5
pseudocode
6
IF
7
NumberOfPlayers
8
4 spaces
9
//
10
INTEGER, REAL, CHAR, STRING, BOOLEAN
Answer Key
IGCSE Computer Science Paper 2 · Modules 136–145 · Student wording will vary for definitions
1CALL — Runs a procedure. A main program is a short list of CALL lines, one per sub-problem from the structure diagram, in the right order, with no detail inside it.
2PROCEDURE — Each box in a structure diagram becomes a PROCEDURE or FUNCTION named after the box. A box with sub-boxes uses CALL statements to run them. Check that every box has code.
3abstract, decompose, draw, write — Abstract the scenario, split it into inputs, processes, outputs and storage, draw a structure diagram, then write a flowchart or pseudocode for each part and check it against the requirements.
4full-mark answer — Uses key terms (sub-system, decomposition, abstraction, input, process, output, storage) correctly and gives a reason for each point, for example by using the word 'because'.
5pseudocode — Cambridge's fixed format for planning an algorithm before it is written as program code. Paper 2 answers must use it, except the 15-mark question, which allows Python, VB or Java.
6IF — IF is a pseudocode keyword. All keywords (IF, ENDIF, WHILE, OUTPUT) are written in upper case and never used as identifier names. Lower case, such as if, is a presentation error.
7NumberOfPlayers — An identifier in Pascal case: a variable or constant name using only letters and digits, starting with a capital, with each word capitalised and no spaces or underscores.
84 spaces — Indent every statement inside a FOR, WHILE or REPEAT loop by 4 spaces. Nested loops add 4 more; wrapped continuation lines use 2. An unindented loop body is a presentation error.
9// — Starts a comment that runs to the end of the line. It explains the code to the reader but is not part of the algorithm, so it is ignored when run.
10INTEGER, REAL, CHAR, STRING, BOOLEAN — The five basic pseudocode data types: whole numbers, decimals, a single character, text of any length, and TRUE or FALSE. A phone number should be a STRING.