I'm a pretty basic programmer and I'm coding a 'Master-mind' style guessing game program.

Now the part I'm stuck with is that I want to go through an array and increase the pointer when I come across a specific number. 

Now thats pretty easy and stuff, but what I want to do is ONLY increase the counter if the number is encountered for the first time. So, for example if there are two numbers (189, 999), I want the counter to increase only once, instead of 3 times, which is what my code is doing. I know why its doing that, but I can't really figure out a way to NOT do it (except maybe declaring an array and putting all the repeated numbers in there and only incrementing it if none of the numbers match, but that's super inefficient) Here's my code:

```
for (int i = 0; i < mString.length(); i++) {
        for (int j = 0; j < nString.length(); j++) {
            if (mString.charAt(i) == nString.charAt(j)) {
                correctNumbers++;
            }
        }
    }

```

Thanks for taking the time to read! I'd prefer it if you wouldn't give me a direct answer and just point me in the right direction so I can learn better. Thanks again!