Write, compile, and execute Cambridge IGCSE (0478), A-Level (9618), IB, and Computer Science algorithms in your browser. Interactive terminal, live linter, trace tables, and cloud saving.
Type your algorithm into the main.pseudo window using standard Cambridge/IB syntax. Click Run Code, and our backend engine will process your logic. If your program asks for data using the INPUT command, type your response directly into the blinking Interactive Terminal.
Our online compiler strictly adheres to the official formats used in major exams. We support full logic processing including IF/THEN/ELSE conditions, nested FOR/WHILE/REPEAT loops, 1-dimensional and 2-dimensional ARRAY structures, and complex string manipulation.
Switch to Pro Mode at the top of the editor to enable our dynamic linter. The interpreter will proactively flag syntax errors—such as unclosed loops, missing ENDIF statements, or incorrect assignment arrows—before you even hit run, helping you write flawless code.
PseudoStudio is the leading web-based pseudocode compiler specifically engineered to execute strict Cambridge International Computer Science pseudocode directly in your browser. Unlike generic programming sandboxes, our parser adheres to official Paper 2 and Paper 4 syllabus mark schemes, eliminating the frustration of compiler errors on legitimate exam syntax.
Whenever your algorithm evaluates an INPUT statement, execution pauses deterministically. Type your response directly into the inline blinking cursor terminal, hit Enter, and execution resumes seamlessly—supporting multiple inputs, loops, and sentinel checks.
Nested display loops and 2-dimensional array outputs are automatically intercepted and rendered as clean, border-aligned ASCII tables in the terminal, letting you dry-run matrix algorithms with complete visual clarity.
Simulate file handling without touching local disks. Use OPENFILE, READFILE, WRITEFILE, APPEND, and EOF loops with our interactive virtual file setup modal, mirroring Cambridge Paper 2 practical file questions.
Our cloud interpreter engine supports all official Cambridge keywords, data structures, and algorithmic routines:
| Language Construct | Cambridge Syntax Pattern | Execution Notes |
|---|---|---|
| Variable & Constant Declarations | DECLARE X : INTEGER CONSTANT Pi = 3.14 |
Supports INTEGER, REAL, CHAR, STRING, and BOOLEAN. |
| Assignment Operator | Count ← Count + 1 | Type <- to automatically render the Cambridge arrow. |
| Conditionals & Selection | IF ... THEN ... ELSE ... ENDIF CASE OF ... OTHERWISE ... ENDCASE |
Full support for nested IF statements and multi-branch CASE. |
| Iteration & Loops | FOR ... TO ... NEXT WHILE ... DO ... ENDWHILE REPEAT ... UNTIL ... |
Deterministic loop execution with infinite loop safeguards. |
| 1D & 2D Arrays | DECLARE Grid : ARRAY[1:5, 1:5] OF INTEGER | Supports strict 1-based indexing as defined in exam syllabuses. |
| Modular Subroutines | PROCEDURE ... ENDPROCEDURE FUNCTION ... RETURNS ... ENDFUNCTION |
Full BYVAL and BYREF parameter passing semantics. |
Yes. PseudoStudio is 100% free for all students, independent learners, and teachers. There are no credit card requirements, no subscription paywalls, and no intrusive pop-up advertisements.
When executing an INPUT statement, our cloud runtime pauses execution and renders a blinking prompt in the black terminal. Simply type your input value and press Enter to continue.
Our engine is purpose-built for Cambridge International IGCSE (0478/0984), O-Level (2210), and AS & A-Level (9618). It also supports AQA, OCR, Pearson Edexcel, and IB Computer Science algorithm conventions.
Solve syllabus-aligned coding challenges and trace tables with instant AI-powered mark scheme grading.
DECLARE MyVar : INTEGER
MyVar ← 10
IF X > 5 THEN
...
ENDIF
CASE OF X
>= 90: OUTPUT "A"
OTHERWISE OUTPUT "B"
ENDCASE
WHILE X < 10
...
ENDWHILE
FOR i ← 1 TO 10
...
NEXT i
INPUT MyVar
OUTPUT "Result: ", MyVar
UCASE("Computer Science")
LCASE("Computer Science")
LENGTH(MyString)
SUBSTRING("Computer Science", 10, 7)
Value1 ← MOD(10, 3)
Value2 ← DIV(10, 3)
Value3 ← ROUND(6.97354, 2)
Value4 ← RANDOM()
Need more than a cheat sheet? Read our full tutorials.
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To consult PseudoAI, give your project a name and save it to your cloud account so your code, terminal logs, and AI conversations are preserved.
We noticed your code has many syntax issues across multiple lines.
Are you trying to paste pseudocode from a Cambridge Paper 2 mark scheme or textbook?
Copy the prompt below, open ChatGPT, Gemini, or any AI, paste it, and attach screenshots of the mark scheme. The AI will give you code that works perfectly in PseudoStudio.
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Your pseudocode interacts with virtual files. Please enter any initial content that should exist inside each file before running: