String Contains

[Trumpman06]

I'm reading in arguments from the command line, and I need test them to see if they contain certain characters. I need to check each argument for 3 characters. one cannot be repeated but the others can. these two repeatable characters cannot be be in the same argument. how can i accomplish this?

[itsme86]

Homework

Make an attempt and if you get stuck ask a specific question. We're not here to do your homework for you.