// CSE 142, Winter 2008, Marty Stepp
//
// This program demonstrates a "sentinel" value,
// a special value that signals the end of user input.
// Sentinel loops are an example of a fencepost problem.
//
// This version of the code uses a constant for the sentinel.

import java.util.*;

public class Sentinel2 {
	public static final int SENTINEL = -1;
	
	public static void main(String[] args) {
		Scanner console = new Scanner(System.in);
		
		// read first number (place first "post")
		System.out.print("Enter a number (" + SENTINEL + " to quit): ");
		int number = console.nextInt();
		int sum = 0;
		
		// read remaining numbers
		while (number != SENTINEL) {
			// add number to sum (place a "wire")
			sum = sum + number;
			
			// read next number (place a "post")
			System.out.print("Enter a number (" + SENTINEL + " to quit): ");
			number = console.nextInt();
		}
		
		System.out.println("The total was " + sum);
	}
}