Make a Calculator class.

It will have the following properties...

• range which should start out as empty array
• primes which should start out as empty array

It should have the following method...

• getPrimes, which should follow the The Sieve of Eratosthenes explanation

The Sieve of Eratosthenes is a simple, ancient algorithm for finding all prime numbers up to any given limit.

A prime number is a natural number that has exactly two distinct natural number divisors: 1 and itself.

Create your range, starting at two and ending at the given limit.

The algorithm consists of repeating the following over and over:

• take the next available unmarked number in your list (it is prime)
• remove all the multiples of that number (they are not prime)

Repeat until you don't have any possible primes left in your range.

When the algorithm terminates, all the numbers in the list that have not been removed are prime.