Cambridge IGCSE Computer Science · Syllabus 0478 · Programming
Counting
What is Counting?
Recording how many times something has happened by adding one to a variable each time an event occurs; the counter is initialised to zero before the loop and incremented only when its condition is satisfied.
This definition is part of the Programming chapter in Cambridge IGCSE Computer Science.
Counting in context
Totalling is accumulating values into a variable: Total ← Total + Value. Counting is recording how many times something happened: Count ← Count + 1. They look almost identical and are constantly confused, but they answer different questions — how much altogether? against how many? — and the value added is different: the data item for a total, always the number 1 for a counter. Both must be initialised to 0 before the loop, and a counter should be incremented only when its condition is satisfied.
Common mistakes with Counting
- M10. “Counting and totalling are the same operation.” TruthA total adds the data value: Total ← Total + Value. A counter adds one: Count ← Count + 1. They answer different questions. WatchA counter that answers “how many that…” must be inside the IF, not after ENDIF.