weather.txt

16.2 23.5
19.1 7.4 22.8
18.5 -1.8 14.9

WeatherData.java

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

public class WeatherData {

	public static void main(String[] args) throws FileNotFoundException {
		
		File f = new File("weather.txt");
		Scanner in = new Scanner(f);
		
		if(in.hasNextDouble()) {
			double d = in.nextDouble();
			while( in.hasNextDouble() ) {
				double d2 = in.nextDouble();
				double change = d2 - d;
				
				System.out.printf("%.1f to %.1f, change = %.1f\n", d, d2, change);
				
				d = d2;
			}
			
		} else {
			System.out.println("Empty file!");
		}
		

	}

}