QuizWeek1/LoopFun.java

public class LoopFun
{

      /**
       * Given a number, return the factorial of that number.
       * For example, given 5, the factorial is 5 x 4 x 3 x 2 x 1 which should return 120.
       * @param number
       * @return the factorial of the number
       */
      public int factorial(int n){
          int result = 0;
          if(n == 0)
          {
              result = 1;
          } else {
              return n * factorial(n - 1);
          }
          return result;
      }

      /**
       * Given a phrase, get the acronym of that phrase. Acronym is the combination of
       * the first character of each word in upper case.
       * For example, given "Ruby on Rails", this method will return "ROR"
       * @param phrase
       * @return Upper case string of the first letter of each word
       */
      public String acronym(String phrase) {
          //String result = "";
          //String newString = "";
          //String phra = phrase;
          //String[] words = phra.split(" ");
          //String word = words[0];
          //if(word.length() > 0){
            //  String[] letters = word.split("");
            //  result += letters[0].toUpperCase();
            //  newString = StringUtilities.searchReplaceFirst(phra, words[0], "");
            //  return result += acronym(newString);
          //}else{
            //  return result;
          //}
          String result = "";
          String[] words = phrase.split(" ");
          
          for(int i = 0; i < words.length; i ++)
          {
              String word = words[i];
              String[] letters = word.split("");
              result += letters[0].toUpperCase();
          }
          return result;
      }

      /**
       * To prevent anyone from reading our messages, we can encrypt it so it will only be readable by its
       * intended audience. This method encrypt the message by shifting the letter by 3 characters. If the character is
       * at the end of the alphabet, it will wraps around.
       * For example:
       *  'a' => 'd'
       *  'w' => 'z'
       *  'x' => 'a'
       *  'y' => 'b'
       * @param word
       * @return the encrypted string by shifting each character by three character
       */
      public String encrypt(String word) {
          char[] chars = word.toCharArray();
          String result = "";
          for(int i = 0; i < chars.length; i ++)
          {
              char currentChar = chars[i];
              int charValue = (int)(currentChar);
              
              for(int m = 0; m < 3; m ++)
              {
                  charValue ++;
                  if(charValue > 122)
                  {
                      charValue = 97;
                  } 
              }
              
              char newChar = (char)(charValue);
              String charString = String.valueOf(newChar);
              System.out.println(charString);
              result += charString;
              
          }
          
          return result;
      }
}