Why should I use asserts?

Question

I never got the idea of asserts -- why should you ever use them?

I mean, let\'s say I were a formula driver and all the asserts were things like security belt, helm

Answer 1

I've written code where the assertions demonstrably affected performance when enabled. Checking the pre- and post-conditions of maths functions used in tight loops by your graphics code, for example (square root function squares its result and compares it against the input, etc). Sure, it's on the order of a few percentage points, but I've written code that needed those few points.

More importantly, I've written code where the assertions made a tens-of-percentage-points difference to the size of the code. When memory footprint is an issue, asserts in release code are probably an unacceptable extravagance.