// CSE 143, Winter 2009, Marty Stepp
// This program uses recursion to print the lines of a file in reverse order.

import java.io.*;
import java.util.*;

public class Poem {
    public static void main(String[] args) throws FileNotFoundException {
        Scanner input = new Scanner(new File("poem.txt"));
        reverseLines(input);
    }
    
    // Prints the lines of the given input file in reverse order, recursively.
    public static void reverseLines(Scanner input) {
        if (input.hasNextLine()) {
            // recursive case: one or more lines; reverse them
            // (the base case is implicitly to do nothing)
            String line = input.nextLine();   // read first line
            reverseLines(input);              // print rest of lines, reversed
            System.out.println(line);         // print first line last
        }
    }

    // original version; also works but does not have "recursion zen"
    public static void reverseLines2(Scanner input) {
        String line = input.nextLine();       // read first line
        if (!input.hasNextLine()) {
            // base case (one line file);  just print the line
            System.out.println(line);
        } else {
            // recursive case (multi-line file)
            reverseLines2(input);             // print rest of lines, reversed
            System.out.println(line);         // print first line last
        }
    }
}