class Main { public static void main(String[] args) { //tells whether a given no. is prime or not ? boolean flag = isPrime(4); System.out.println("4 is prime ?" +flag); flag = isPrime(432); System.out.println("43 is prime ?" + flag); } static boolean isPrime(int N) { boolean check = true; if (N == 1 || N == 0) { check = false; } else { //run till the square root of the number for (int i =2; i<= Math.sqrt(N); i++) { if(N%i == 0) { check = false; break; } } } return check; } }