Coders Rock

Practice

Challenges

16 short challenges across 8 sets, in the same order as the lessons on Learn to Write Code. Every one runs in pseudocode, Python, and JavaScript, so you can write the same idea three ways and see that it is the same idea.

Nothing is locked, nothing is scored, and we keep nothing. Start where you like.

Set 01

Variables & Data

Store a value, change it, and show it.

First scoreboard

Create two variables, change one of them, then show both.

Swap two values

Move two values past each other without losing either one.

Set 02

Operators & Comparisons

Do arithmetic, and ask questions that answer true or false.

Receipt total

Add up a bill, then ask whether it cleared a threshold.

Odd or even

Use a remainder to tell odd numbers from even ones.

Set 03

Input, Output & Comments

Ask a question, use the answer, and leave a note for the next reader.

Greet by name

Ask for a name and greet the person who typed it.

Two questions

Collect two answers and use them in one sentence.

Set 04

Program Structure & Sequence

Order matters -- run the steps in the order the result needs.

Morning routine

Put four steps in an order that actually works.

Read before you write

See why a value has to exist before anything can use it.

Set 05

Conditions & Branching

Let the program choose between two or more paths.

Ticket price

Choose one of three prices from one number.

Both must be true

Combine two questions into one decision.

Set 06

Loops & Repetition

Repeat work without writing it out over and over.

Count down

Run a loop backwards and stop at the right moment.

Running total

Build one answer out of many passes through a loop.

Set 07

Functions & Reuse

Write something once and use it as many times as you like.

Area of a room

Take two values in, send one answer back.

Shout it

Build a small helper and call it from a loop.

Set 08

Objects & Blueprints

Describe a thing once, then make as many of them as you need.

Two players

Prove that two objects from one blueprint hold separate values.

Highest score

Walk a list of objects and pick one out.