Email Pattern Macro

Need a macro that will autofill in an email pattern from a customer list i recieve. So far i have been having to manually do it.. but when have documents over 3k entries.. ouch.

This is what i got.. hope the way i type it in makes sense
A ..........................B ..........................C
First name........Last Name ............Email Pattern
John ..................Smith ...............First name initial, last name@abc.com
John ..................Smith ...............First name initial, dot, last name@abc.com
John ..................Smith ...............First name, dot, last name@abc.com
John ..................Smith ...............First name, initial of last name@abc.com

Is there a macro i can make that will automatically fill in the email based on the criterea found in column C before the @ symbol? then take the required info from Column a and b?