[PHP知识库]Java黑皮书课后题第10章：*10.15（几何：边框）边框是指包围一个二维平面上点集的最小矩形，编写一个方法，为二维平面上一系列点返回一个边框

题目

点击这里跳转编程练习题10.13

程序

Test15.java：测试程序
Test13_MyRectangle2D.java：编程练习题10.13构造程序

代码

Test15.java

import java.util.Scanner;

public class Test15 {
    public static void main(String[] args) {
        // 获取5个点的坐标
        double[][] points = new double[5][2];
        System.out.print("Enter five points: ");
        Scanner input = new Scanner(System.in);
        for (int m = 0 ; m < 5 ; m++){
            for (int n = 0 ; n < 2 ; n++){
                points[m][n] = input.nextDouble();
            }
        }

        // 结束结果
        Test13_MyRectangle2D mt = getRectangle(points);
        System.out.print("The bounding rectangle's center (" + mt.getX() + ", " + mt.getY() +
                "), width " +mt.getWidth() + ", height " + mt.getHeight());
    }
    public static Test13_MyRectangle2D getRectangle(double[][] points){
        double xMax = points[0][0], yMax = points[0][1], xMin = points[0][0], yMin = points[0][1];
        for (int a = 0 ; a < points.length ; a++){
            if (points[a][0] > xMax)
                xMax = points[a][0];
            if (points[a][0] < xMin)
                xMin = points[a][0];
            if (points[a][1] > yMax)
                yMax = points[a][1];
            if (points[a][1] < yMin)
                yMin = points[a][1];
        }
        return new Test13_MyRectangle2D((xMax + xMin) / 2, (yMax + yMin) / 2, xMax - xMin, yMax - yMin);
    }
}

Test13_MyRectangle2D.java

public class Test13_MyRectangle2D {
    private double x, y;
    public double getX() {
        return x;
    }
    public void setX(double x) {
        this.x = x;
    }
    public double getY() {
        return y;
    }
    public void setY(double y) {
        this.y = y;
    }

    private double width, height;
    public double getWidth() {
        return width;
    }
    public void setWidth(double width) {
        this.width = width;
    }
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }

    public Test13_MyRectangle2D(){
        x = 0;
        y = 0;
        width = 1;
        height = 1;
    }
    public Test13_MyRectangle2D(double x, double y, double width, double height){
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
    }

    public double getArea(){
        return width * height;
    }

    public double getPerimeter(){
        return 2 * (width + height);
    }

    public boolean contains(double x, double y){
        boolean bool1 = false, bool2 = false;
        if (x > this.x - width / 2 && x < this.x + width / 2)
            bool1 = true;
        if (y > this.y - height / 2 && y < this.y + height / 2)
            bool2 = true;
        return bool1 && bool2;
    }

    public boolean contains(Test13_MyRectangle2D r){
        return ((Math.abs(x - r.x)) < width / 2) && (Math.abs(y - r.y) < height / 2);
    }

    public boolean overlaps(Test13_MyRectangle2D r){
        return ((Math.abs(x - r.x)) < (width / 2 + r.width / 2)) && (Math.abs(y - r.y) < (height / 2 + r.height / 2));
    }
}

运行结果

Enter five points:1.0 2.5 3 4 5 6 7 8 9 10
The bounding rectangle's center (5.0, 6.25), width 8.0, height 7.5