# Not quite a Sieve of Eratosthanes

### Chapter 3: Parameterized typing with generics: 3.5.1

Created: 2/22/2008

Last updated: 2/22/2008

The method for finding primes in listing 3.13 isn't quite the normal Sieve of Eratosthanes - because it removes multiples of numbers we already know to be non-prime. There's no simple way to change the listing while keeping the point of it (i.e. the use of `RemoveAll`

) which is why I kept it as it is.

We *could* check the list of candidates in the second `for`

loop, to see if `factor`

is present - but of course this ends up being reasonably expensive too if performed in the simplest manner. A binary search would be quicker, but then we're getting significantly more complicated.