Software Engineering › Key terms › Code patterns › Binary selection (IF THEN ELSE)
Binary selection (IF THEN ELSE)
Code pattern Code patterns
Definition
IF condition THEN process ELSE other process ENDIF: one of two paths is taken.
Example
IF age >= 18 THEN DISPLAY "Adult" ELSE DISPLAY "Minor" ENDIFFound in: course specifications, past SDD papers.
Where it is used in the test
Syllabus area: Code patterns.
Question types it can appear in
- Pseudocode: Use it correctly in the exam pseudocode editor.
- Code reading: Code or algorithm reading: interpret a fragment and state its output or purpose.
- Drawing: Draw or label it in the online drawing tool.
Where it has appeared in the paper
The Software Engineering Project (Part A). Part letters follow each paper’s own layout.
Related past questions
- 2025 HSC Q17 (3 marks): Algorithm design The Software Engineering Project (Part A) · 3 marks
These are the questions the flashcard set links to this term. Open each one and compare your answer with its marking criteria.
Study links
- Flashcard: Binary selection (IF THEN ELSE) in Code Patterns: Pseudocode, Python, SQL, CSS (Years 11 and 12) · study that set
- Memorise: Python and SQL you must be able to write
- Notes: Control structures in HSC pseudocode (Pseudocode, flowcharts and diagram rules)
How to use it in an answer
A model sentence
Code pattern: “IF condition THEN process ELSE other process ENDIF: one of two paths is taken.” Then apply it: IF age >= 18 THEN DISPLAY "Adult" ELSE DISPLAY "Minor" ENDIF
In a short answer, give the definition in your own words first, then tie it to the situation in the question. Do not copy the example above unless it fits the scenario.
Technique for the question types
- Pseudocode: Write HSC-style pseudocode: capital keywords, paired END words, indentation; initialise variables; output the required result.
- Drawing: Use the online drawing tool: label every symbol and arrow, use the correct symbols from the specification, and add every required item.
What the marking guidelines and feedback say
Marker feedback: use pseudocode control structures accurately; iterate an array and sum it; apply relational operators correctly; use the stimulus to choose the right structures.
Common mistakes
- Pseudocode questions (2025 HSC exam Q17): use pseudocode control structures accurately; iterate an array and sum it; apply relational operators correctly; use the stimulus to choose the right structures.
- Drawing questions (2025 HSC exam Q22): refine attributes into separate inherited classes; use appropriate class diagram symbols.
- Use the term exactly as the syllabus words it, then link it to the scenario in the question; the 2025 feedback repeatedly rewards using the stimulus.
- Answer the command word: outline gives main points only, explain gives a reason or cause, discuss gives both sides.
Related terms
Same group in the syllabus: Pseudocode keywords · Sequence · Multi-way selection (CASEWHERE) · Nested IF · WHILE loop (pre-test) · REPEAT UNTIL loop (post-test) · FOR / NEXT loop (counted) · Subroutine and function (pseudocode) · Array sum pattern · Linear search pattern