我想计算Java中两点之间的距离

Question

好的,所以我编写了大部分程序,可以让我确定两个圆是否重叠.

除了一个问题,我的程序没有任何问题:程序不会接受我为两个中心点之间的距离编写的代码.我可以弄清楚if/else逻辑告诉用户取决于稍后的距离值会发生什么,但我想知道现在有什么问题.Eclipse,我编写的程序,告诉我应该将距离解析为数组,但我已经告诉过你它是一个int.

这是我的代码:

package circles;
import java.util.Scanner;

public class MathCircles {    
    // variable for the distance between the circles' centers
    public static int distance;

    // variable for the lengths of the radii combined
    public static int radii;

    public static void main(String[] args) {
        // Get the x-value of the center of circle one
        System.out.println("What is the x-coordinate for the center of circle one?");
        Scanner keyboard = new Scanner(System.in);
        int x1 = keyboard.nextInt();

        //Get the y-value of the center of circle one
        System.out.println("What is the y-coordinate for the center of circle one?");
        Scanner keyboard1 = new Scanner(System.in);
        int y1 = keyboard1.nextInt();

        //Get the radius length of circle one.
        System.out.println("How long is circle one's radius?");
        Scanner keyboard2 = new Scanner(System.in);
        int r1 = keyboard2.nextInt();

        // Get the x-value of the center of circle two.
        System.out.println("What is the x-coordinate for the center of circle two?");
        Scanner keyboard3 = new Scanner(System.in);
        int x2 = keyboard3.nextInt();

        //Get the y-value of the center of circle two.
        System.out.println("What is the y-coordinate for the center of circle two?");
        Scanner keyboard4 = new Scanner(System.in);
        int y2 = keyboard4.nextInt();

        //Get the radius length of circle two.
        System.out.println("How long is circle two's radius?");
        Scanner keyboard5 = new Scanner(System.in);
        int r2 = keyboard5.nextInt();

        /*
         * OK, so now I have the location of the two circles' centers,
         * as well as the lengths of their radii.
         * The circles are intersecting IF THE DISTANCE BETWEEN THE TWO CENTERS
         * IS EQUAL TO OR LESS THAN THE COMBINED LENGTHS OF THE RADII.
         * Now I need to get some math done.
         */

        //calculate the combined lengths of the radii

        radii = r1 + r2;

        //calculate the distance
        distance = Math.sqrt((x1-x2)(x1-x2) + (y1-y2)(y1-y2));

    }    
}

Answer 1

根据@ trashgod的评论,这是计算距离的最简单方法:

double distance = Math.hypot(x1-x2, y1-y2);

从文件中Math.hypot:

返回:sqrt(x²+ y²) 没有中间溢出或下溢.

Answer 2

与maths-on-paper表示法不同,大多数编程语言(包括Java)都需要一个*符号来进行乘法运算.因此,您的距离计算应为:

distance = Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));

或者:

distance = Math.sqrt(Math.pow((x1-x2), 2) + Math.pow((y1-y2), 2));

Answer 3

这可能是旧的,但这是最好的答案:

    float dist = (float) Math.sqrt(
            Math.pow(x1 - x2, 2) +
            Math.pow(y1 - y2, 2) );

Answer 4

根据@trashgod的评论，这是计算>距离的最简单方法：

double distance = Math.hypot(x1-x2, y1-y2); 从Math.hypot的文档中：

返回：sqrt(x²+ y²)没有中间上溢或下溢。

鲍勃

在鲍勃（Bob）的认可评论下方，他说他无法解释

Math.hypot(x1-x2, y1-y2);

做到了。解释一个三角形有三个边。使用两个点，您可以根据x,y每个点的长度找到这些点的长度。Xa=0, Ya=0如果考虑的直角坐标为(0,0)，然后再按Xb=5, Yb=9，则直角坐标为(5,9)。因此，如果将它们绘制在网格上，则假设x到另一个x在相同的y轴上的距离为+5。假设它们在同一x轴上，沿Y轴到另一个的距离为+9。（认为​​数字线）因此三角形长度的一侧是5，另一侧是9。斜边是

 (x^2) + (y^2) = Hypotenuse^2

这是三角形剩余边的长度。因此与标准距离公式完全相同

 Sqrt of (x1-x2)^2 + (y1-y2)^2 = distance 

因为如果您取消了操作左侧的sqrt，而改为使用distance ^ 2，那么您仍然必须从该距离获取sqrt。因此，距离公式是勾股定理，但在某种程度上，教师可以称其为混淆人的东西。