error: no match for ' ' problem

[Paul McKenzie]

how would I go about formatting the isdigit and isalpha line to make it a string instead?

isdigit is a function that tests a single character to see if it is a digit. Similarly, the isalpha tests a single character to see if it is an alphabetic character.

So there is no way to "format" these functions to do something they are not written to do. You have to write your own routine to test if an entire string is whatever you feel it should be.

Regards,

Paul McKenzie