using System; class ChkNum { // Return true if x is prime. public bool isPrime(int x) { for(int i=2; i <= x/i; i++) if((x %i) == 0) return false; return true; } } class MainClass { public static void Main() { ChkNum ob = new ChkNum(); for(int i=1; i < 10; i++) if(ob.isPrime(i)) Console.WriteLine(i + " is prime."); else Console.WriteLine(i + " is not prime."); } }
1 is prime. 2 is prime. 3 is prime. 4 is not prime. 5 is prime. 6 is not prime. 7 is prime. 8 is not prime. 9 is not prime.