The loop that never ends
This page needs a recent browser (with SharedArrayBuffer support). Please update Chrome, Edge, Firefox or Safari to the latest version.
This one builds on a lesson you haven't finished yet. Do that lesson first:
Python Basics · While loops →
The loop that never ends
Run this first and watch what happens. The line that makes count smaller is there — but it is outside the loop, so it never runs.
In Python the indentation is the structure: lines indented under while belong to the loop and repeat, a line back at the left margin comes after the loop and runs once at the end. Here the loop never reaches its last line, so its question stays true for ever. The page will notice and stop it for you, but your program should stop itself.
Run this first and watch what happens. The line that makes count smaller is there — but it is outside the loop, so it never runs. Move it inside so the program prints 5, 4, 3, 2, 1 and stops.
Click Run to see the output here.