How many cards do I need?

JavaScript Beginner robot ages 11-13 From CS Unplugged

The problem

Write a function bitsNeeded(n). It gives back how many binary cards (bits) you need to show the number n. n is 1 or more. Example: 5 needs 3 cards (4, 2 and 1).

You will practice: while loops, doubling, counting

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CC BY-SA 4.0

Adapted from a CS Unplugged programming challenge by the University of Canterbury Computer Science Education Research Group, licensed CC BY-SA 4.0.

Original challenge · License: CC BY-SA 4.0

Changes: Rewritten in our own words as a function with tests, hints and steps, in Python and JavaScript, by Open Cosmos. This version is also CC BY-SA 4.0.