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){
        
        if(number == 1){
            return number;
        }
        number *= factorial(number-1);
        return number;
    }

    /**
     * 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[] arr = phrase.split(" ");
       String acronym = "";
       for(int i = 0; i < arr.length; i++){
          acronym += arr[i].toUpperCase().charAt(0);
        
        }
        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 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) {
        String[] encrypted = word.split("");
        char start = 'a';
        //start = (char) (((start-'a'+3) %26) + 'a');
        String fin = "";
        for(int i = 0; i < encrypted.length; i++){
            fin += String.valueOf((char) (((encrypted[i].charAt(0)-'a'+3) %26) + 'a'));
        }
        return fin;
    }
}