UVa 465 - Overflow

// UVa 465 - Overflow

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()) {

            String line = scanner.nextLine();

            String[] tokens = line.split(" ");
            String sa = tokens[0];
            String sb = tokens[tokens.length - 1];
            char operator = '?';
            for (int i = 1; i < tokens.length - 1; i++)
                if (!tokens[i].equals("")) {
                    operator = tokens[i].charAt(0);
                    break;
                }

            BigInteger a = new BigInteger(sa);
            BigInteger b = new BigInteger(sb);

            BigInteger c = (operator == '+')
                    ? a.add(b)
                    : a.multiply(b);

            System.out.println(line);
            warnIfNecessary("first number", a);
            warnIfNecessary("second number", b);
            warnIfNecessary("result", c);
        }
    }

    private static final BigInteger LIMIT = BigInteger.valueOf(Integer.MAX_VALUE);

    private static void warnIfNecessary(String prefix, BigInteger number) {
        if (number.compareTo(LIMIT) > 0) {
            System.out.println(prefix + " too big");
        }
    }
}