Hi Drup,
Judging by your ques you need a book on biginning COBOL. Go to half.com and search on "beginning cobol"; you'll get a list of used books ranging in cost from $1 to $35. Order the $1 book (cost you more in S&H). You'll begin to understand.
How did your ques originate? Did your instuctor ask? How did he pose the ques?
What is your take on the topic? How would you use it? Have you written a pgm? Have you written or read records to and from a file? Have you wondered about how many records you've written and/or read?
I ask these ques because of the ques you ask. Some indicate that you have an idea of what a counter may be; some don't.
Regards, Jack.