Define a bool function named IsLower() that takes a char parameter. It returns true if the parameter is a lowercase letter; otherwise, it returns false. Define a bool function named IsUpper() that takes a char parameter. It returns true if the parameter is an uppercase letter; otherwise, it returns false. Define an int function named LetterCount() that takes a string parameter. It returns the count of the letters in the parameter. Define a string function named ToLower() that takes a string parameter. It returns a string that is a duplicate of the parameter except all the uppercase letters of the parameter are turned to lowercase letters in the string. Define a string function named ToUpper() that takes a string parameter. It returns a string that is a duplicate of the parameter except all the lowercase letters of the parameter are turned to uppercase letters in the string. Define a string function named Substr() that takes a string parameter and two char parameters named str , s and e respectively. It returns a substring of str that starts with the character s and ends with the character e. If s is not a member of str , the function returns an empty string. Furthermore, if e is not a member of str , the function returns a substring that starts with s and ends with the last character of str .

In C++, please.