Prime number program in Java.

Following is the required program.

Example

Live Demo

public class Tester {
   public static void main(String args[]) {
      int i, m = 0, flag = 0;
      int n = 41;// it is the number to be checked
      m = n / 2;
      if (n == 0 || n == 1) {
         System.out.println(n + " not a prime number");
      } else {
         for (i = 2; i <= m; i++) {
            if (n % i == 0) {
               System.out.println(n + " not a prime number");
               flag = 1;
               break;
            }
         }
         if (flag == 0) {
            System.out.println(n + " is a prime number");
         }
      }
   }
}

Output

41 is a prime number.