Question

我的问题是当我们将j=i+1更改为j = 0或更改时会发生什么 j = i。我的意思是这两种情况有什么区别？

import java.util.Scanner;

public class FindNearestPoints {
  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];
    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; // Initial two points
    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

        if (shortestDistance > distance) {
          p1 = i; // Update p1
          p2 = j; // Update p2
          shortestDistance = distance; // Update shortestDistance 
        }
      }
    }

    // Display result
    System.out.println("The closest two points are " +
      "(" + points[p1][0] + ", " + points[p1][1] + ") and (" +
      points[p2][0] + ", " + points[p2][1] + ")");
  }

  /** 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));
  }
}

Answer 1

如果设置j = i，那么最小距离将为零，因为您要计算点与自身之间的距离！

如果您设置了j = 0，则上述内容仍适用，但由于您要包含j == i，因此会包含不必要的重复内容。

Answer 2

当我们将mEditText.setOnKeyListener((v, keyCode, event) -> { //for submiting result if ((keyCode == KeyEvent.KEYCODE_SPACE || keyCode == KeyEvent.KEYCODE_ENTER) && mEditText.getText().toString().length() > 0) { // Your Positive button's code over here } return false; });更改为j=i+1或j = 0

时

我们第一次到达代码中的j = i时，会生成变量j并初始化为for statement。

将其更改为任何其他值，我们将获得不同的初始化值。

当我们改变循环中的值时会发生什么？

2 个答案: