which number is prime number code example

Example 1: prime number

a number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11)
suppose a number 'n' it can be divided by if '1' and only by itself then it can be a prime number

Example 2: prime number

public class Prime {
    public static void main(String[] args) {

        int num = 29;
        boolean flag = false;
        for(int i = 2; i <= num/2; ++i){
            if(num % i == 0){
                flag = true;
                break;
            }
        }

        if (!flag)
            System.out.println(num + " is a prime number.");
        else
            System.out.println(num + " is not a prime number.");
}}