public class KategoriPort {
    static String kategori(int port) {
        if (port < 0 || port > 65535) {
            return "tidak valid";
        }
        if (port == 0) {
            return "ephemeral (dipilih sistem)";
        }
        if (port < 1024) {
            return "well-known";
        }
        if (port < 49152) {
            return "registered";
        }
        return "dynamic/ephemeral";
    }

    public static void main(String[] args) {
        int[] contoh = {80, 443, 8080, 0, 53100, 70000};
        for (int port : contoh) {
            System.out.printf("port %-6d -> %s%n", port, kategori(port));
        }
    }
}