Question

I am writing code for the game Mastermind/Bulls and Cows. I am randomly generating a code (length determined by user) and the user has to try to guess it. I need to think of a way to compare the code and the guess to determine how many "cows" (right number, wrong place) and "bulls" (right number, right place) there are. I have a way to separate each digit to compare to the other ones using objects that were pre-made for this. Comparing to find bulls is easy becuase you can just compare the digits in each position. The issue is the cows. How do you find a way to compare each digit to the other