/* T01n13.java -- Given a message typed by the user, find all periods and
 * replace them with exclamation points, and find all exclamation points
 * and add another exclamation point after each one.  For example:
 *   Hey! Slow down.  --->  Hey!! Slow down! 
 *
 * This is the second of three examples that do this same task, but in 
 * different ways:
 *
 *    T01n12.java -- Using Strings, build the new string a character at a time
 *    T01n13.java -- Still using only Strings, use substring() to build the
 *                   new string in chunks (uses fewer concatenations).
 *    T01n14.java -- Convert the input into a StringBuilder object and
 *                   manipulate it directly.
 *
 * Can you think of a more efficient way to locate the next period or
 * exclamation point?
 */

import java.util.*;

public class T01n13
{
    public static void main (String [] args)
    {
        String message;                     // User's boring/exciting message
        Scanner keyboard = new Scanner (System.in);  // Input is from keyboard

        System.out.print("Please type in a message : "); 
        message = keyboard.nextLine();

        message = addExcitement(message);

        System.out.println("\nThank you.  If you had been more excited, "
                         + "you'd have typed your message\nlike this:\n\t"
                         + message);
    }

            /* This version of addExcitement builds the new string a group
             * of characters at a time.  We locate the next . or !, and then
             * add the whole group of characters ahead of it to the new string 
             * before adding the ! or the !! as appropriate.  We contine until
             * no more . and ! remain, and finish by adding the remaining
             * characters to the new string and returning it.
             */

    private static String addExcitement (String original)
    {
        String excited = "";   // Reference to built-up resulting message
        int  currentChar = 0,  // *Index* of current punctuation character
             firstPeriod,      // closest subsequent (.) w.r.t. current loc.
             firstExclamation, // closest subsequent (!) w.r.t. current loc.
             earliest;         // location of closest subsequent (.) or (!)

        while (true) {

                        // Starting where we left off, find the next
                        // occurrences of . and !

            firstPeriod = original.indexOf('.',currentChar);
            firstExclamation = original.indexOf('!',currentChar);

                        // If we can't find any more of either, leave loop

            if (firstPeriod < 0 && firstExclamation < 0) {
                break;
            } else {

                        // At least one . or ! exists in the remainder of
                        // the user's message.  Find the location of the
                        // closest one.

                if (firstPeriod >=0 && firstExclamation >= 0) {
                    earliest = Math.min(firstPeriod,firstExclamation);
                } else if (firstPeriod >=0 && firstExclamation < 0) {
                    earliest = firstPeriod;
                } else {
                    earliest = firstExclamation;
                }

                        // Add the group of characters ahead of the
                        // . or ! to the new string

                excited += original.substring(currentChar,earliest);

                        // Add excitement by converting the characters

                if (original.charAt(earliest) == '.') {
                    excited += '!';
                } else { 
                    excited += "!!";
                }

                        // Move beyond the . or ! we just dealt with

                currentChar = earliest + 1;

            }
        }
                        // The characters after the last . or ! still need
                        // to be added to the new string to complete our work.

        excited += original.substring(currentChar,original.length());

        return excited;
    }

}