C# 计算素数

这段代码通过BitArray来计算素数

using System.Collections;
...
const int LAST_CANDIDATE = 1000;
int primes = 0;
BitArray candidates = new BitArray (LAST_CANDIDATE, true);
 
for (int i = 2; i < LAST_CANDIDATE; i++)
{
   if (candidates[i])
   {
      for (int j = i * 2; j < LAST_CANDIDATE; j += i)
         { candidates[j] = false; }
   }
}
 
for (int i = 1; i < LAST_CANDIDATE; i++)
{
   if (candidates[i])
   {
      primes++;
      Console.Out.WriteLine (i);
   }
}
 
Console.Out.WriteLine
   ("\n" + primes + " primes found in the range 2-" + LAST_CANDIDATE);