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 number){
          int fact = 1;
          for(int i = 1; i <= number; i++)
          {
              fact *= i;
          }
          return fact;
      }

      /**
       * 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[] strArr = phrase.split(" ");
          String acronym = "";
          for(int i = 0; i < strArr.length; i++)
          {
              String tempStr = strArr[i].substring(0, 1);
              acronym = acronym.concat(tempStr.toUpperCase());
          }
          return acronym;
      }

      /**
       * 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 wrap around.
       * For example:
       *  'a' => 'd'
       *  'w' => 'z'
       *  'x' => 'a'
       *  'y' => 'b'
       * @param word
       * @return the encrypted string by shifting each character by three character
       * ansi 97 ('a') to 122 ('z')
       */
      public String encrypt(String word) {
          char[] charArr = word.toCharArray();
          for(int i = 0; i < charArr.length; i++)
          {
              int tempInt = ((int)charArr[i]) + 3;
              if(tempInt > 122)
              {
                  tempInt -= 26;
              }
              charArr[i] = (char)tempInt;
          }
          String returnStr = new String(charArr);
          return returnStr;
      }
}