Prime Number Formula

Question

I am trying to write a prime number function in C# and I am wondering if the follow code will work. It \"appears\" to work with the first 50 numbers or so. I just want to ma

Answer 1

This approach definitely won't work, unless your if statement explicitly enumerates all the prime numbers between 0 and sqrt(INT_MAX) (or the C# equivalent).

To properly check for primality, you basically need to attempt to divide your number by every prime number less than its square root. The Sieve of Eratosthenes algorithm is your best bet.