package ip;

import java.util.Scanner;

/**
 * @author Zigi
 */
public class IP {

    private static final int IP_PARTS = 4;
    private static final int START = 0;
    private static final int STOP = 1;
    private static final int INPUT_SIZE = 2;
    private static final int PART = 256;
    private static final int PART2 = 256 * 256;
    private static final int PART3 = 256 * 256 * 256;

    private static boolean isValidIP(final String[] parts)  {
        if(parts.length != IP_PARTS) {
            System.out.print("Invalid IP structure! ");
            return false;
        }

        for(int i = 0; i < IP_PARTS; i++){
            int partNum = -1;
            try {
                partNum  = Integer.parseInt(parts[i]);
            } catch (NumberFormatException e) {
                System.out.print("Non-number entered at position " + (i + 1) + "! ");
                return false;
            }
            if (partNum < 0 || partNum >= PART) {
                System.out.print(
                    "The number at position " + (i + 1) +
                    " should be in the range [0; 255]! "
                );
                return false;
            }
        }

        return true;
    }

    private static long getNumber(final String[] parts) {
       long number = 0L, exp = 24L;

       for(int position = 0; position < IP_PARTS; position++){
           number += (long)Integer.parseInt(parts[position]) << exp;
           exp -= 8L;
       }
       return number;
    }

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String parts[][] = new String[INPUT_SIZE][];
        String types[] = {"first", "last"};

        for(int i = 0; i < INPUT_SIZE; i++)
            do {
                System.out.print("Please input " + types[i] + " ip address: ");
                String ip = input.nextLine();
                parts[i] = ip.split("\\.");
            } while (!isValidIP(parts[i]));

        long start = getNumber(parts[START]), stop = getNumber(parts[STOP]) + 1;
        for(long ip = start; ip < stop; ip++) {
            System.out.println(
                ip / PART3 % PART + "." +
                ip / PART2 % PART + "."  +
                ip / PART % PART + "."  +
                ip % PART
            );
        }
    }
}