Largest and Smallest Digit

/*
 * Problem : Find the largest and the smallest digit.
 * Input   : One integer.
 * Output  : Two lines.
 * Approach: Keep the best digit seen so far.
 * Time    : O(d)
 * Space   : O(1)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        long number = Math.abs(new Scanner(System.in).nextLong());

        // Step 1: Start with values that any digit will replace. Digits are between 0 and 9.
        int largest = 0;
        int smallest = 9;

        // Step 2: A do-while loop runs at least once, so the number 0 is also checked.
        do {
            // Step 3: Take the last digit. Example: 2859 % 10 = 9.
            int digit = (int) (number % 10);

            // Step 4: Keep the largest and the smallest digit seen so far.
            if (digit > largest) {
                largest = digit;
            }
            if (digit < smallest) {
                smallest = digit;
            }

            // Step 5: Remove the last digit. Example: 2859 / 10 = 285.
            number = number / 10;
        } while (number > 0);

        // Step 6: Print the results.
        System.out.println("Largest digit: " + largest);
        System.out.println("Smallest digit: " + smallest);
    }
}