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 sum=1;
        for(int i=1;i<=number;i++)
        { 
            sum=sum*i;

        }return sum;
    }

    /**
     * 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 = phrase.replaceAll("\\B.|\\P{L}", "").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) {
        String s = "";
        int shift = 3;
        int len = word.length();
        for (int i =0; i <len; i++) {
            char c = (char) (word.charAt(i) + shift);
            if (c > 'z') {
                s += (char) (word.charAt(i) - (26-shift));
            } else { 
                s+= (char) (word.charAt(i) + shift);
            }
            
        }
        
        return s;

 
}

}