/***************************************************************************************

* *

* CODERBYTE BEGINNER CHALLENGE *

* *

* Letter Changes *

* Using the JavaScript language, have the function LetterChanges(str) take the str *

* parameter being passed and modify it using the following algorithm. Replace every *

* letter in the string with the letter following it in the alphabet *

* (ie. c becomes d, z becomes a). Then capitalize every vowel in this new string *

* (a, e, i, o, u) and finally return this modified string. *

* *

* SOLUTION *

* You have to realize that the string passed in may contain items other than letters *

* of the alphabet. If you find a character that is not a-z then just pass it along *

* to the newStr as is without any modification. I am going to compare each letter *

* in the string to the alphabet string. If the letter is found then I am going to *

* return the next letter in the string unless the letter is z and them I am going *

* to return a. When finished I am going to use a RegExp to replace all lower case *

* vowels with upper case.

* *

* Steps for solution *

* 1) Create alphabet string that contains all letters of the alphabet *

* 2) Loop through each letter in the string *

* 3) If letter is Z then return a *

* 4) If letter is not a-z then return letter as is to newStr *

* 5) If letter is a-z then return the next character in the alphabet string *

* 6) Replace all vowels with upper case with a RegExp replace() function *

* *

***************************************************************************************/

function LetterChanges(str) {

var alphabet = "abcdefghijklmnopqrstuvwxyz";

var newStr = "";

var loc;

for (var i = 0; i < str.length; i++) {

loc = alphabet.indexOf(str[i]);

if (loc === 25) {

newStr = newStr + "a";

} else if (loc === -1) {

newStr = newStr + str[i];

} else {

newStr = newStr + alphabet[loc + 1];

}

}

return newStr.replace(/[aeiou]/g, function(letter) {return letter.toUpperCase()});

}