Tracks
/
Elixir
Elixir
/
Exercises
/
Eliud's Eggs
Eliud's Eggs

Eliud's Eggs

Easy

Introduction

Your friend Eliud inherited a farm from her grandma Tigist. Her granny was an inventor and had a tendency to build things in an overly complicated manner. The chicken coop has a digital display showing an encoded number representing the positions of all eggs that could be picked up.

Eliud is asking you to write a program that shows the actual number of eggs in the coop.

The position information encoding is calculated as follows:

  1. Scan the potential egg-laying spots and mark down a 1 for an existing egg or a 0 for an empty spot.
  2. Convert the number from binary to decimal.
  3. Show the result on the display.

Example 1

Seven individual nest boxes arranged in a row whose first, third, fourth and seventh nests each have a single egg.

 _ _ _ _ _ _ _
|E| |E|E| | |E|

Resulting Binary

1011001

 _ _ _ _ _ _ _
|1|0|1|1|0|0|1|

Decimal number on the display

89

Actual eggs in the coop

4

Example 2

Seven individual nest boxes arranged in a row where only the fourth nest has an egg.

 _ _ _ _ _ _ _
| | | |E| | | |

Resulting Binary

0001000

 _ _ _ _ _ _ _
|0|0|0|1|0|0|0|

Decimal number on the display

16

Actual eggs in the coop

1

Instructions

Your task is to count the number of 1 bits in the binary representation of a number.

Restrictions

Keep your hands off that bit-count functionality provided by your standard library! Solve this one yourself using other basic tools instead.

Edit via GitHub The link opens in a new window or tab
Elixir Exercism

Ready to start Eliud's Eggs?

Sign up to Exercism to learn and master Elixir with 57 concepts, 159 exercises, and real human mentoring, all for free.