It will be no good for someone to give a solution to you without you working through the solution on your own.

You should see your teacher if you are having problems. That is the only way he will know if he is covering the material well enough for the students.

I panicked(?) when I got a programming assignment at school and I went to see the teacher. He didn't give a solution, but re-assured me that the assignment wasn't that difficult. He might have also given some idea where to head for a solution.

I would keep count of the numbers (and their repetitions) in a hash for file 1, then open the second file and print out the counts in the from file 1 for each number in file 2.