We ask the user to enter a phrase (It could be a single word or a sentence with spaces). The user isn't going to be able to introduce a number as a character or to leave the answer window blank.
After this the program is going to assign each character its ASCII number, then is going to assign the character its number in the decimal count (1-26). Finally is going to return the new letter in a new string.
PSEUDOCODE
FLOWCHART