LC Computer Science study guide
LC Computer Science · Work through your exam, one topic at a time.
Leaving Certificate Computer Science is a Senior Cycle subject in Ireland. Curriculum Online defines it as 'the study of computing and algorithmic processes', and says the course covers how programming and computational thinking can be applied to the solution of problems, and how computing technology impacts the world around us. That definition is a good test of whether the subject suits you: it is not a typing or office-skills course, and it is not only theory. You will spend time writing code, tracing algorithms and debugging, and you will also be expected to write clearly about the effects of computing on people and society. Topics on this exam: Practices and principles, Core concepts, and Computer science in practice. The LC Computer Science study guide has 3 sections and about 1,240 words.
01Practices and principles
This domain tests how you think and build: computational thinking, program construction and design. The paper gives you an unfamiliar problem and asks you to break it down, express a solution unambiguously, and read or write code by hand. Python is the usual language; pseudocode is acceptable provided every step is precise. Four moves carry most of the marks.
426 words, about 2 min02Core concepts
This domain tests the machinery beneath the code: how data is represented, how algorithms behave as input grows, how a processor executes instructions, and how machines exchange messages. Binary is base 2; one byte is 8 bits, giving 256 unsigned values (0–255). Two’s complement encodes negatives with the most significant bit as the sign, so the 8-bit range is −128 to 127. One hex digit is exactly four bits, so a byte is always two hex digits.
431 words, about 2 min03Computer science in practice
This domain tests whether you can carry a project from brief to evaluation and reason about computing’s effect on people. It is where the applied learning tasks live and where the long-answer security, legal and ethics questions come from. From a brief, produce functional and non-functional requirements, a design (inputs, processes, outputs, interface sketch, data model), an implementation, a test plan, and an evaluation judged against the original requirements with evidence rather than opinion. Keep artefacts that show process - drafts, commit history, revised designs - because marks reward iteration, not just the finished program.
383 words, about 2 min