public class Distance {
    public static void main(String[] args) {
        printWelcomeMessage();
        
        Scanner console = new Scanner(System.in);
        
        System.out.println("Pair 1:");  
        double distance1 = getDistance(console);
        System.out.println();

        System.out.println("Pair 2:");  
        double distance2 = getDistance(console);
        System.out.println();
        
        System.out.println("Pair 1 is " + distance1 + " apart");
        System.out.println("Pair 2 is " + distance2 + " apart");
        
        // distance1 < distance2   --> pair 1 is closer
        // distance2 < distance1   --> pair 2 is closer
        
        // nested if / else statement
 /*
        if (distance1 < distance2) {
            System.out.println("Pair 1 is the closer pair.");
        }
        else {
            // distance1 >= distance2
            if (distance1 > distance2) {
                System.out.println("Pair 2 is the closer pair.");
            }
            else {
                // distance1 == distance2
                System.out.println("The two pairs have equal distance.");
            }
        }
 */     
        if (distance1 < distance2) {
            System.out.println("Pair 1 is the closer pair.");
        }
        else if (distance1 > distance2) {
            System.out.println("Pair 2 is the closer pair.");
        }
        else {
            // distance1 == distance2
            System.out.println("The two pairs have equal distance.");
        }
       
    }
    
    public static double getDistance(Scanner console) {
        System.out.print("    Enter a point's x and y coordinate: ");
        double x1 = console.nextDouble();
        double y1 = console.nextDouble();

        System.out.print("    Enter a point's x and y coordinate: ");
        double x2 = console.nextDouble();
        double y2 = console.nextDouble();
        double distance1 = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2));
        return distance1;
    }
    
    public static void printWelcomeMessage() {
        System.out.println("This program reads two pairs of (x, y) points from the user");
        System.out.println("and computes the distance between each pair, then reports");
        System.out.println("the distances.");
    }
}