**8.8 (All closest pairs of points) Revise Listing 8.3, FindNearestPoints.java, to display all closest pairs of points with the same minimum distance. Here is a sample run: Enter the number of points: 8 Enter 8 points: 0 0 1 1 -1 -1 2 2 -2 -2 -3 -3 -4 -4 5 5 The closest two points are (0.0, 0.0) and (1.0, 1.0) The closest two points are (0.0, 0.0) and (-1.0, -1.0) The closest two points are (1.0, 1.0) and (2.0, 2.0) The closest two points are (-1.0, -1.0) and (-2.0, -2.0) The closest two points are (-2.0, -2.0) and (-3.0, -3.0) The closest two points are (-3.0, -3.0) and (-4.0, -4.0) Their distance is 1.4142135623730951
import java.util.Scanner; public class ProgramingEx8_8 { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.print("Enter the number of points: "); int numberOfPoints = input.nextInt(); // Create an array to store points double[][] points = new double[numberOfPoints][2]; int[][] sortestPoints = new int[numberOfPoints][2]; System.out.print("Enter " + numberOfPoints + " points: "); for (int i = 0; i < points.length; i++) { points[i][0] = input.nextDouble(); points[i][1] = input.nextDouble(); } // p1 and p2 are the indices in the points array int p1 = 0, p2 = 1, n = 0; // Initial two points and shortest distance // array index (n) sortestPoints[n][0] = p1; sortestPoints[n][1] = p2; double shortestDistance = distance(points[p1][0], points[p1][1], points[p2][0], points[p2][1]); // Initialize shortestDistance // Compute distance for every two points for (int i = 0; i < points.length; i++) { for (int j = i + 1; j < points.length; j++) { double distance = distance(points[i][0], points[i][1], points[j][0], points[j][1]); // Find distance // check the difference between the distance and the shortest // distance to a threshold if (Math.abs(shortestDistance - distance) < 10e-6) { // new pair for points with shortest distance found n++; sortestPoints[n][0] = i; sortestPoints[n][1] = j; } else if (shortestDistance > distance) {// New shortest // distance found n = 0; sortestPoints[n][0] = i; sortestPoints[n][1] = j; shortestDistance = distance; // Update shortestDistance } } } // Display result for (int i = 0; i < n + 1; i++) { p1 = sortestPoints[i][0]; p2 = sortestPoints[i][1]; System.out.println("The closest two points are " + "(" + points[p1][0] + ", " + points[p1][1] + ") and (" + points[p2][0] + ", " + points[p2][1] + ")"); } System.out.println("Their distance is " + shortestDistance); } /** Compute the distance between two points (x1, y1) and (x2, y2) */ public static double distance(double x1, double y1, double x2, double y2) { return Math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1)); } }
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