cc++ help please and thank you.

Function 2 Function Name: Function Parameters: Function Return: Function Description: EncryptString string (by reference) int (Number of characters to shift by) bool This function will perform a Caesar Cipher shift (http://en.wikipedia.org/wiki/Caesar_cipher). If the string contains any non-alpha characters do not perform the encryption and return false. Otherwise perform the encryption and return true. Function 3 Function Name: Function Parameters: Function Return: Function Description: DecryptString string (by reference) int (Number of characters the string was shifted by) bool This function decrypts a Caesar Cipher shift. If the string contains any non-alpha characters do not perform the decryption and return false. Otherwise perform the encryption and return true