// CSE 143, Summer 2012
// This program includes code for several recursive methods.

// For each of these methods, we identified:
// 		- the easiest version of the problem to solve (base case)
// 		- a small piece of the problem we could solve that gets us 
//			closer to the base case (recursive case)

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

public class Recursion {
	public static void main(String[] args) throws FileNotFoundException {
	/*	System.out.println(pow(2, 3)); // 8
		System.out.println(pow(5, 2)); // 25
		System.out.println(pow(153, 3)); // 3 581 577
		System.out.println(pow(6, 1)); // 6

		printBinary(2); // 10
		System.out.println();
		printBinary(12); // 1100
		System.out.println();
		printBinary(-500); // 111110100
		System.out.println();
	
		System.out.println(isPalindrome("madam")); // true
		System.out.println(isPalindrome("step on no pets")); // true
		System.out.println(isPalindrome("Java")); // false
	
	*/
		reverseLines(new Scanner (new File("cookie.txt")));
	
	}
	
	

	// Returns the base raised to the exponent
	// Pre: exponent >= 0
	public static int pow(int base, int exp) {
		if (exp == 0) {
			return 1;
		} else if (exp % 2 == 0) {
			// call pow passing our new values 
			return pow (base * base, exp / 2);
		} else {
			return base * pow (base, exp - 1);
		}
	}



	// Accepts an integer in base-10 as its parameter.
	// Prints that number's base-2 representation.
	public static void printBinary(int n) {
		if (n < 0) {
			System.out.print("-");
			printBinary(-n);
		} else if (n < 2) {
			System.out.print(n);
		} else { // 101010
			printBinary(n / 2);  // 10101
			printBinary(n % 2);  // 0
		}
	}





	// returns true if the string is the same backwards
	// and forwards.
	public static boolean isPalindrome(String s) {
		if (s.length() < 2) {
			return true;
		} else {
			char first = s.charAt(0);
			char last = s.charAt(s.length() - 1); 
			if (first != last) {
				return false;
			}
			String middle = s.substring(1, s.length() - 1);
			return isPalindrome(middle);
		}
	}
	
	
	
	
	public static boolean isPalindromeNinja(String s) {
		return true;
	}
	
	
	
	// reverses the lines in the input
	public static void reverseLines(Scanner input) {
	    if (input.hasNextLine()) {
		 	String line = input.nextLine();
			reverseLines(input);	 
			System.out.println(line);
		 }
	}

}