How to make c++ script to modify games money and gems in android..

Answer 1

If a game is coded right you don't. Such things are normally server side. You could manipulate the client to show another value than the actual value, but you can't use the gems/money, because the database still knows that you are too poor to buy certain in-game things.
Beside that your account could be banned when you manipulate the client.
And even if it was possible: Noone here would show you how to do it...

Answer 2

so please sugest me another language.