An array is a data structure for holding many values of the same type.

An algorithm is a procedure for computing something.

It's sort of like the difference between an egg carton and a recipe. An egg carton will hold one or more eggs, up to some fixed maximum size. A recipe will tell you how to cook something, and may or may not involve eggs.

Array is congreagation of numbers(1,2,3, etc). Algorithm is way to solve problems particularly programming problems.