Example: maximum of positive integers read from a file

Recursive characterization of the operation of finding the maximum among a set of values read from a file that contains positive integers:

• if the file is finished, return 0;
• otherwise,
  1. read an integer i from the file;
  2. find the maximum m among the remaining values in the file;
  3. return the bigger one between i and m.

Implementation: we access the file through a BufferedReader, and we assume that each integer is written on a separate line.

public static int maximum(BufferedReader br) throws IOException {
  String s = br.readLine();
  if (s == null)
    return 0;
  else {
    int i = Integer.parseInt(s);
    int m = maximum(br);
    return (m > i)? m : i;
  }
}