I'm not sure if I've understood correctly what you want to do, because you've essentially answered your own question, but...
you can define any variables you like in a script or function, so
kp=0
will work fine as long as it's not within a loop. Then, if you wish to increment it each time through a process or iteration just include the incrementing statement in the loop. You can also nest loops if needed.
Look up commands "for" and "while" in Matlab help to read about loops and see some examples.
