Debugging: find, isolate, correct

Debugging is the deliberate process of locating, isolating, and correcting a fault in a system, whether it is a broken spreadsheet formula, a programming loop, or even a policy workflow. The key contrast is with testing: testing reveals that a bug exists, but debugging is the step where you actually fix it. In an exam, if a question describes someone running checks to see if a formula works, that is testing; if they then trace through cell references to find why the result is wrong and correct it, that is debugging.

A practical trick is to mentally split debugging into three phases: reproduce the error consistently, isolate the exact line or cell where the logic breaks, then apply the fix. If you are given a multiple-choice scenario, look for verbs like "trace", "step through", or "inspect" to spot debugging, versus "run", "verify", or "check" for testing. Another trap: debugging is not the same as error handling in code — error handling anticipates problems, while debugging reacts to an existing fault.

To remember the distinction, think of a doctor: testing is like taking a patient's temperature to see if they are ill (finding a symptom), while debugging is diagnosing the cause and prescribing treatment (fixing the underlying issue). In an exam, if a question says "the program runs but gives wrong output", the next logical step is debugging, not retesting.