Java Program to check if a number is prime

/** * * @program To check if entered number is prime or not */ import java.io.*; class Prime { public static void main(String args[]) throws IOException { BufferedReader k = new BufferedReader(new InputStreamReader(System.in)); System.out.println("Enter number"); int num = Integer.parseInt(k.readLine()); if(isPrime(num)) System.out.println(num + " is a prime number"); else System.out.println(num + " is not a prime number"); } static boolean isPrime(int n) { //since 2 is the only even prime number if(n > 2 && n % 2 == 0) return false; //check odd numbers that are prime for(int i = 3;i < Math.sqrt(n)+1 ; i=i+2){ if(n%i == 0) return false; } return true; } }

Java Program for prime testing.