Yes, the length of each line.

Suppose I have a file with the lines:
Today is tuesday.
Tomorrow is Wednesday.

I have to find the length of the first line which I can do by character by character reading till I reach a '\n' with a count of the number of characters but then I have to go back to the beginning of the line again to read the contents of the line and put in the buffer which is allocated the number I obtained by the first level of counting.