This introduction covers The Bouncer at the Door within Input Validation for GCSE Computer Science. Revise Input Validation in Robust Programs for GCSE Computer Science with 15 exam-style questions and 8 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 1 of 5 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 1 of 5
Practice
15 questions
Recall
8 flashcards
The Bouncer at the Door
Validation is like a bouncer at a club - checking everyone meets the entry requirements before letting them in. You can't have negative age, a 47-character postcode, or £999,999 in a £50 limit account. Validation catches these impossible values *before* they break your program. It doesn't guarantee data is correct (someone could enter age 25 when they're 52), but it ensures data is sensible and won't crash the system.