Function to find the sum of prime frequencies of the characters of the given string
static void sumProdOfPrimeFreq ( char [ ] s ) { int i ; bool [ ] prime = new bool [ s . Length + 1 ] ; for ( i = 0 ; i < s . Length + 1 ; i ++ ) { prime [ i ] = true ; } SieveOfEratosthenes ( prime , s . Length + 1 ) ;