// This program demonstrates several new concepts, including:
//   - String methods (charAt, length, etc.)
//   - fencepost loops
//   - while loops
//   - sentinel loops
//   - random numbers
//   - String cumulative "sum"
import java.util.*;

public class LoopPractice {
   public static void main(String[] args) {
      System.out.println(doubleLetters("hello"));
      System.out.println(doubleLetters("Mississippi"));
      System.out.println(doubleLetters("abracadabra"));
      System.out.println();
   
      spellOut("hello");
      spellOut("abracadabra");
      spellOut("supercalifragilisticexpialidocious");
      System.out.println();

      spellOutAlt("hello");
      spellOutAlt("abracadabra");
      spellOutAlt("supercalifragilisticexpialidocious");
      System.out.println();
      
      for (int i = 1; i < 5; i++) {
         rollDice();
         System.out.println();
      }
      
      Scanner console = new Scanner(System.in);
      System.out.println(concatenateAll(console));
   }
   
   // Returns a new String with each character from the given String
   //   doubled.
   // e.g. hello -> hheelllloo
   //
   // String word - the String whose letters should be doubled
   public static String doubleLetters(String word) {
      String result = "";
      for (int i = 0; i < word.length(); i++) {
         // String letter = word.substring(i, i + 1);
         char letter = word.charAt(i);
         result = result + letter + letter;
      }
      return result;
   }   
   
   // Prints out the the characters in the given String separated
   //  by dashes.
   // e.g. hello -> h-e-l-l-o
   //
   // String word - the String to print
   public static void spellOut(String word) {
      System.out.print(word.charAt(0));
      for (int i = 1; i < word.length(); i++) {
         System.out.print("-" + word.charAt(i));
      }
      System.out.println();
   }
   
   // Alternate version of spellOut that removes the last instance
   //   of the fencepost instead of the first.
   //
   // String word - the String to print
   public static void spellOutAlt(String word) {
      for (int i = 0; i < word.length() - 1; i++) {
         System.out.print(word.charAt(i) + "-");
      }
      System.out.println(word.charAt(word.length() - 1));
   }
   
   // Simulates rolling a six-sided die repeatedly until a 6 is rolled,
   //   counting how many rolls are made.
   public static void rollDice() {
      Random rand = new Random();
      int roll = rand.nextInt(6) + 1;
      int count = 1;
      while (roll != 6) {
         System.out.println("You rolled a " + roll);
         roll = rand.nextInt(6) + 1;
         count++;
      }
      System.out.println("You rolled a 6!");
      System.out.println("You won in " + count + " rolls.");
   }   
   
   // Reads in a sequence of words from the user until "quit" is typed,
   //   then returns all the typed words (except "quit") concatenated
   //   together.
   public static String concatenateAll(Scanner console) {
      String result = "";
      System.out.print("Next word (or \"quit\" to end): ");
      String word = console.next();
      while (!word.equals("quit")) {
         result += word;
         System.out.print("Next word (or \"quit\" to end): ");
         word = console.next();         
      }
      return result;
   }
}