Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

array

A fixed-length, numbered row of values of one type.

An object holding a fixed number of elements of one type, indexed from 0 to length - 1 and reached through a reference.

Examples

int[] scores = {90, 75, 88}; has length 3 and indexes 0 to 2.