is there a function to determine if prime number exists in the sum?

Question

i have constants that represents a prime number. for example,

  enum Signals : long
    {
        LONGPULLBACK = 2,
        SHORTPULLBACK = 3,
        RSIOVERSOLD = 5,
        RSIOVERBOUGHT = 7,
        BOUGHTSIGNAL = 9,
        DOUBLEBOUGHTSIGNAL = 11,
        SOLDSIGNAL = 13,
        DOUBLESOLDSIGNAL = 17,
        MATRENDINGLONG = 19,
        MATRADENINGSHORT = 23


    }

for every signal triggered, i just add it to the sum. there will always be only 1 signal of each type triggered. when i have a sum of 25, is there a function to return the prime number parts of the sum ie 2,23?

Answer 1

No.

But you can achieve what you want by using flags. Just don't use 0 as one of your flags for one of the values in your list. 0 can only denote None because you'll never be able to check whether a 0 was added. And the values must be powers of 2. So: 1, 2, 4, 8, ... And only up to 63 values (besides the 0) if you're using long to account for the sign bit. I think you can get 64 if you're using ulong.

Example:

[Flags]
enum Signals : long
{
   None = 0,
   LONGPULLBACK = 1,
   SHORTPULLBACK = 2,
   RSIOVERSOLD = 4,
   RSIOVERBOUGHT = 8,
   //etc.
};

(I'll add that what you were trying to do would work if you were multiplying the numbers. But that would make the number pretty big. Also, decomposition wouldn't be as simple.)