How to use this
An unofficial practice tool for the pseudocode used in Cambridge International AS & A Level Computer Science (9618). Every question here is original, written in the style of the syllabus.
The problem this solves. Pseudocode marks are lost on mechanics, not on ideas. You know a loop is needed; you write FOR i = 1 TO 10 instead of FOR i ← 1 TO 10, forget the NEXT i, and drop two marks you had earned. This app drills the mechanics until they are automatic.
Work through it in this order:
- Course (01) — twelve lessons from assignment through to OOP. Each ends with a check question. Start here even if you think you know the syntax; Lesson 1 is where most marks leak.
- Practice (02) — the question bank. Write an answer, then use the tips ladder if you are stuck. Tips go from a nudge to a near-answer, so take only as many as you need.
- Exam mode (03) — a timed set with tips switched off. Mark yourself against the mark scheme at the end.
- Reference (04) — the whole syntax on one page, for when you are mid-question and cannot remember whether it is ENDWHILE or END WHILE.
This app contains a real interpreter for 9618 pseudocode. Press Run it under any practice question and your answer is executed — loops loop, arrays fill up, files are read, classes are instantiated. You get the output, or you get told exactly what is wrong and on which line.
The errors are the point. It knows the mistakes that cost marks and names them the way a teacher would:
- '=' cannot be used to store a value in a variable.
- NEXT names 'j' but this FOR loop counts with 'i'.
- 'Total' has been declared but nothing has been put in it yet.
- Index 6 is outside 'Scores', which runs from 1 to 5.
- You cannot divide by zero. A count that is still 0 is the usual cause.
Where a question says data already exists — “an array that already holds the monthly rainfall” — that data is really there when you run it, so the output means something.
In Practice you can run your answer as often as you like, read the error, fix it and run again. That is how you learn where your syntax leaks.
In Exam mode the Run button is gone. When the timer stops, every executable answer is run once. If it does not run, that question scores zero and its mark scheme is locked — the same way an algorithm that does not work earns nothing. You still see the error afterwards, so you know what to drill.
Every answer box is a pseudocode editor with three conveniences built in:
- Type <- and it becomes ← automatically. In the real exam you write the arrow by hand, so get used to seeing it.
- Tab indents by four spaces, Shift+Tab outdents. Indentation is worth marks.
- Press Enter after a line ending in THEN, DO, REPEAT and it auto-indents the next line.
Pseudocode answers are marked on logic, not spelling. An examiner reading your answer asks: could I follow this and get the right result? You are not required to match the syllabus keywords exactly — but matching them removes all doubt, and doubt costs marks.
Mark schemes award a mark per identifiable step. If you write nothing you score nothing, but a partially correct algorithm with a clear structure usually picks up half the marks. Never leave a pseudocode question blank. Write the declarations, the loop, and the output even if the middle is wrong.
The course
Twelve lessons, in order. Each one teaches the syntax, shows it working, names the mistake that loses marks, and ends with a question you answer before moving on.
Practice bank
Pick a question, write your answer, then reveal tips one at a time only when you are stuck. Mark yourself honestly against the mark scheme — the score is only useful if it is true.
The library
Every keyword and every built-in function for your course, each with an example you can run and edit. Nothing here is a claim you have to take on trust — press Run and watch it work.
Progress
Self-marked totals per topic. Weak topics sort to the top, because that is where the next hour of revision should go.