import java.net.*;


public class AddressTests {

  public static int getVersion(InetAddress ia) {
    
    byte[] address = ia.getAddress();
    if (address.length == 4) return 4;
    else if (address.length == 16) return 6;
    else return -1;
    
  }

  public static char getClass(InetAddress ia) {
  
    byte[] address = ia.getAddress();
    if (address.length != 4) {
      throw new IllegalArgumentException("Do not understand IPv6 addresses!");
    }
  
    int firstByte = address[0];
    if ((firstByte & 0x80) == 0) return 'A';
    else if ((firstByte & 0xC0) == 0x80) return 'B';
    else if ((firstByte & 0xE0) == 0xC0) return 'C';    
    else if ((firstByte & 0xF0) == 0xE0) return 'D';
    else if ((firstByte & 0xF8) == 0xF0) return 'E';
    else return 'F';
    
  }

}