アルゴリズム:素数

public class $ {

    public static void main(String[] args) {

        for (int i = 1; i <= 100; i++) {

            if (i == 1) {
                System.out.println("1         .");
                continue;
            }

            if (check(i)) {
                System.out.println(i);
            }
        }
    }

    private static boolean check(int num) {

        int sqrt = (int) Math.sqrt(num);
        for (int j = 2; j < sqrt + 1; j++) {

            if (num % j == 0) {
                return false;
            }
        }
        return true;
    }
}