Write a C++ program that prompts the user to enter a letter and encrypt it using the following method: if the letter is an upper-case letter the program replaces the letter by the 7th letter in the sequence of letters, if the letter is a lower-case letter the program replaces the letter by the 11th letter in the sequence of letters. The program then prints the new letter. Sample Input/Output Enter a letter: D The encrypted version of D is K Enter a letter: w The encrypted version of w is h Enter a letter: Y The encrypted version of Y is F