Listed below are snippets from a program to perform input validation for a username and password. The code to input and validate the username is in a separate file than the code to input and validate the password.

Define the username variable and the isValid() function in the unnamed namespace so the code will compile. The isValid() function should return true if username contains exactly eight letters. Generate an appropriate header file for this code.
Repeat the same steps for the file password.cpp, placing the password variable and the isValid() function in the unnamed namespace:

For passwords, isValid() should require the password to have eight or more letters and at least one non-letter. Generate an appropriate header file for this code as well.

At this point, you should have two functions named isValid(), each in different unnamed namespaces. Place the following main function in an appropriate place. The program should compile and run.