internal static List <int> PrimeFactors(int x)
{
List <int> pf = new List <int>();
//if even, loop till not even any more
while (IsEven(x))
{
//Console.WriteLine(x);
x >>= 1; // shift right is divide by zero
pf.Add(2);
}
// now handle odd
// start with the smallest odd prime
// and work upto half of number
PrimeProvider pp = new PrimeProvider();
foreach (int p in pp.StepPrimes())
{
//Console.WriteLine($"x : {x} :: p: {p}");
if (p > x)
{
break;
}
while (x % p == 0)
{
x /= p;
pf.Add(p);
}
}
return(pf);
}
internal static void Test_YieldConcept()
{
PrimeProvider pp = new PrimeProvider();
foreach (int i in pp.Even())
{
Console.WriteLine(i);
if (i > 100)
{
break;
}
}
}
internal static void Test_StepPrime()
{
PrimeProvider pp = new PrimeProvider();
foreach (int i in pp.StepPrimes())
{
Console.WriteLine($"i : {i}");
if (i > 100)
{
break;
}
}
}