ICDL Coding Principles (ICDL) study guide
ICDL Coding Principles · Work through your exam, one topic at a time.
The ICDL Coding Principles credential sits within the ICDL family of digital-skills certifications, aimed at learners who want a recognised starting point in computer programming rather than a vendor-specific developer qualification. It suits school and college students, career changers, and employees whose roles increasingly touch automation, scripting, or software-adjacent work. Candidates are typically preparing for a first, structured exposure to how code is written and reasoned about, so the emphasis is on transferable concepts rather than fluency in one language. The published domain structure splits the exam evenly between two areas: Coding Principles, and Computational Thinking and Problem Solving. Topics on this exam: Coding Principles and Computational Thinking and Problem Solving. The ICDL Coding Principles study guide has 2 sections and about 690 words.
01Coding Principles: Structure, Readability and Correctness
Coding principles are the habits that make a program understandable, maintainable and dependable, independent of any particular language. A candidate should be able to name and apply: naming conventions (descriptive identifiers, consistent case style), indentation and layout (block structure made visible), comments (explaining why , not restating what ), modularity (small single-purpose functions, parameters instead of hidden globals), constants over magic numbers , defensive input handling (validation, range checks), and avoiding duplicated logic (the DRY idea). You should also recognise the difference between a syntax error (the code cannot be parsed), a runtime error (it parses but fails while executing, e.g. division by zero or an out-of-range index), and a logic error (it runs and produces a wrong answer).
341 words, about 2 min02Computational Thinking and Problem Solving
Computational thinking is a way of framing a problem so that a machine (or a person) can solve it reliably. Four ideas anchor it. Decomposition breaks a large problem into smaller sub-problems that can be tackled separately. Abstraction strips away detail that does not matter for the current task, keeping only the essential features.
349 words, about 2 min