Create a boolean array " prime [ 0 . . n ] " and initialize all entries it as true . A value in prime [ i ] will finally be false if i is Not a prime , else true .
static bool [ ] prime = new bool [ ( int ) ( MAX + 1.0 ) ] ; static void SieveOfEratosthenes ( ) { for ( int i = 0 ; i <= MAX ; i ++ ) prime [ i ] = true ; prime [ 1 ] = false ; for ( int p = 2 ; p * p <= MAX ; p ++ ) {