// Determines if a file of numbers contains any adjacent duplicates
// 	Uses 'sentinel' value for initial 'previous' number (assumes sentinel can't appear in file) 

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

public class DupChecker {
	public static void main(String [] args) throws Exception {
		Scanner keyboard = new Scanner(System.in);

		System.out.print("filename? ");
		String filename = keyboard.next();

		Scanner scanner = new Scanner(new File(filename));

		int previousNumber = -1;

		while (scanner.hasNextInt()) {
			int num = scanner.nextInt();
			if (num == previousNumber) {
				System.out.println("There is at least one pair of adjecent duplicates in the file");
				System.exit(0);
			}
			previousNumber = num;
		}

		System.out.println("No adjacent duplicates found");
	}
}