Video narration
Writing the same printf line again and again for a countdown feels pointless, right? A countdown timer gives us the picture: start with count equal to five. In Online GDB, write: while count is greater than zero, print count, then decrease it by one. First, check the condition. At five, it is true, so the body prints five. Update count to four. Repeat this: four, three, two, one. Here's the key turn: repetition is not automatic. The while loop continues only while the condition is true and the variable changes. At zero, the condition is false, so it stops. Forget the update, and count stays five: an infinite loop. Every round follows the same order; nothing happens automatically. In Online GDB, run it and watch the countdown prove it: condition, body, update, repeat-until zero ends the timer.