It will be no good for someone to give a solution to you without you working through the solution on your own.
in reply to frequency strings 2 files
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.