面向对像程序设计第二次博客作业

一、前言

　 　1、oop-2022-4的题目考察了正则表达式和容器的运用以及对类的设计，题量适中，第一三题不难，经过前三次大作业的锻炼，面对这种题目已经能够从容应对了，第二题是建立在前三次大作业中对图形的理解，用到了许多关于三角形、线和点的属性和方法，难度较大

   2、期中考试的题目则考察的主要的类的设计以及继承和多态的使用和容器，题量适中，在规定考试时间内能够按时完成，题目简单。

　 　3、oop-2022-5的题目也是建立在第四次大作业上，考察对类的设计以及对于各种数学方法的运用，题量大，难度大。

二、设计与分析

（1）第四次作业的设计分析总结

　　1、第一题是从一段文本中获取出数字并对其进行加和，棋本质考察的就是正则表达式，可以创建一个Pattern类的对象，里面包含数字的正则表达式，再运用matcher类里的.find方法对其文本中的数字进行查找，找到后再将其强制转换为double型最后加和输出即可，带代码如下

 

 

　　2、第二题主要考察对四边形的计算，我们可以对四边形进行拆分，创建出点、线、三角形以及四边形类，每个类中包含有自己的 属性和方法，比如Point类中包含有x和y两个属性，并含有各自的setter和getter方法，Line类中则包含两个Point类的属性，并有众多数学方法。三角形和四边形则更是如此，含有许多的数学方法，代码如下

import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {    
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();
        InputData d = new InputData();
        ParseInput.paseInput(s, d);
        int choice = d.getChoice();
        ArrayList ps = d.getPoints();
        switch (choice) {
        case 1:
            handle1(ps);
            break;
        case 2:
            handle2(ps);
            break;
        case 3:
            handle3(ps);
            break;
        case 4:
            handle4(ps);
            break;
        case 5:
            handle5(ps);
            break;
        }
    }

    public static void handle1(ArrayList<Point> ps) {
        
        PointInputError.wrongNumberOfPoints(ps, 4);
        Tetragon t = new Tetragon(ps.get(0), ps.get(1), ps.get(2), ps.get(3));
        if(t.isTetragon()) {
            if(t.IsParallelogram())
                System.out.println(true+" "+true);
            else
                System.out.println(true+" "+false);
        }
        else
            System.out.println(false+" "+false);
    }

        public static void handle2(ArrayList<Point> ps) {
            boolean b1,b2,b3;
            PointInputError.wrongNumberOfPoints(ps, 4);
            Tetragon t = new Tetragon(ps.get(0), ps.get(1), ps.get(2), ps.get(3));
            if(t.isTetragon()) {
                b1=t.Isrhombus();
                b2=t.IsRectangle();
                if(b1&&b2)
                    b3=true;
                else
                    b3=false;
                System.out.println(b1+" "+b2+" "+b3);
            }
            else
                System.out.println("not a quadrilateral");
        }

        public static void handle3(ArrayList<Point> ps) {
            boolean b;
            PointInputError.wrongNumberOfPoints(ps, 4);
            Tetragon t = new Tetragon(ps.get(0), ps.get(1), ps.get(2), ps.get(3));
            if(t.isTetragon()) {
                b=t.IsConvex();
                System.out.println(b+" "+OutFormat.doubleFormat(t.getPerimter())+" "+OutFormat.doubleFormat(t.getArea()));
            }
            else
                System.out.println("not a quadrilateral");
        }    

        public static void handle4(ArrayList<Point> ps) {
            PointInputError.wrongNumberOfPoints(ps, 6);
            Line l = new Line(ps.get(0), ps.get(1));
            Tetragon t = new Tetragon(ps.get(2), ps.get(3), ps.get(4), ps.get(5));
            Triangle tri;
            
            if(t.isTetragon()) {
                if(t.judgeLineCoincide(l))
                    System.out.println("The line is coincide with one of the lines");
                else
                    System.out.println("1");
            }
            else if(t.points()!=null)
            {
                tri = new Triangle(t.points()[0],t.points()[1],t.points()[2]);
                if(tri.judgeLineCoincide(l)) {
                    System.out.println("The line is coincide with one of the lines");
                }
                else {
                    if(tri.getIntersections(l).size()==2) {
                        Point A = tri.getIntersections(l).get(0);
                        Point B = tri.getIntersections(l).get(1);
                        
                        if(A.equals(tri.getX())||A.equals(tri.getY())||A.equals(tri.getZ())) {
                            System.out.println(tri.getIntersections(l).size()+" "+OutFormat.doubleFormat(tri.calTriangleArea(A, B)[0])+" "+OutFormat.doubleFormat(tri.calTriangleArea(A, B)[1]));
                        }
                        else    
                            System.out.println(tri.getIntersections(l).size()+" "+OutFormat.doubleFormat(tri.calArea(A, B)[0])+" "+OutFormat.doubleFormat(tri.calArea(A, B)[1]));
                    }
                    else
                        System.out.println(tri.getIntersections(l).size());
                }
            }
            else if(t.PointsisTriangle()!=null)
            {
                tri = t.PointsisTriangle();
                if(tri.judgeLineCoincide(l)) {
                    System.out.println("The line is coincide with one of the lines");
                }
                else {
                    if(tri.getIntersections(l).size()==2) {
                        Point A = tri.getIntersections(l).get(0);
                        Point B = tri.getIntersections(l).get(1);
                        
                        if(A.equals(tri.getX())||A.equals(tri.getY())||A.equals(tri.getZ())) {
                            System.out.println(tri.getIntersections(l).size()+" "+OutFormat.doubleFormat(tri.calTriangleArea(A, B)[0])+" "+OutFormat.doubleFormat(tri.calTriangleArea(A, B)[1]));
                        }
                        else    
                            System.out.println(tri.getIntersections(l).size()+" "+OutFormat.doubleFormat(tri.calArea(A, B)[0])+" "+OutFormat.doubleFormat(tri.calArea(A, B)[1]));
                    }
                    else
                        System.out.println(tri.getIntersections(l).size());
                }
            }
            else
                System.out.println("not a quadrilateral or triangle");
        }

        public static void handle5(ArrayList<Point> ps) {
            PointInputError.wrongNumberOfPoints(ps, 5);
            Point p = ps.get(0);
            Tetragon t = new Tetragon(ps.get(1), ps.get(2), ps.get(3), ps.get(4));
            Triangle tri;
            
            if(t.isTetragon()) {
                if(t.isInside(p)==1) {
                    System.out.println("in the quadrilateral");
                }
                else if(t.isInside(p)==0)
                    System.out.println("on the quadrilateral");
                else
                    System.out.println("outof the quadrilateral");
            }
            else if(t.points()!=null) {
                tri = new Triangle(t.points()[0],t.points()[1],t.points()[2]);
                if(tri.isInside(p)==1) {
                    System.out.println("in the triangle");
                }
                else if(t.isInside(p)==0)
                    System.out.println("on the triangle");
                else
                    System.out.println("outof the triangle");
            }
            else if(t.PointsisTriangle()!=null) {
                tri = t.PointsisTriangle();
                if(tri.isInside(p)==1) {
                    System.out.println("in the triangle");
                }
                else if(t.isInside(p)==0)
                    System.out.println("on the triangle");
                else
                    System.out.println("outof the triangle");
            }
            else
                System.out.println("not a quadrilateral or triangle");
        }
}
class InputData {
    private int choice;;//用户输入的选择项
    private ArrayList<Point> points = new ArrayList();//用户输入的点坐标
    public int getChoice() {
        return choice;
    }
    public void setChoice(int choice) {
        this.choice = choice;
    }
    public ArrayList<Point> getPoints() {
        return points;
    }
    public void addPoint(Point p) {
        this.points.add(p);
    }
}
class Line {
    private Point p1;//线上的第一个点
    private Point p2;//线上的第二个点

    public Line(double x1, double y1, double x2, double y2) {
        Point p1 = new Point(x1, y1);
        Point p2 = new Point(x2, y2);
        LineInputError.pointsCoincideError(p1, p2);//两点是否重合，重合则报错并退出
        this.p1 = p1;
        this.p2 = p2;
    }
    
    public double getlength() {    
        return Math.sqrt((p1.getX() - p2.getX())*(p1.getX() - p2.getX())+(p1.getY() - p2.getY())*(p1.getY() - p2.getY()));
    }

    public Line(Point p1, Point p2) {
        LineInputError.pointsCoincideError(p1, p2);//两点是否重合，重合则报错并退出
        this.p1 = p1;
        this.p2 = p2;
    }

    public Double getSlope() {
    
        return (p2.getY() - p1.getY()) / (p2.getX() - p1.getX());
    }

    public boolean isOnline(Point x) {

        // 点重合
        if ((x.getX() == p1.getX() && x.getY() == p1.getY()) || (x.getX() == p2.getX() && x.getY() == p2.getY())) {
            return true;
        }
        Line l = new Line(p1, x);
        if (l.getSlope().isInfinite() && this.getSlope().isInfinite()) {
            return true;
        }

        double b1 = l.getSlope(), b2 = this.getSlope();
    
        return Math.abs(b1 - b2)  < 0.00000000001;// b1==b2;
    }

    public double getDistance(Point x) {
        double distY = p2.getY() - p1.getY();
        double distX = p2.getX() - p1.getX();
        return Math.abs(x.getX() * distY - x.getY() * distX - p1.getX() * distY + p1.getY() * distX)
                / p1.getDistance(p2);
    }

    public boolean isBetween(Point x) {
        //System.out.println("isBetween" + " " + this.p1.x + " " + p1.y + " " + p2.x + " " + p2.y + " " + x.x + " " + x.y);
        if (!this.isOnline(x)) {
            return false;
        }
        
        if (x.equals(p1) || x.equals(p2)) {
            return false;
        }
        double d = p2.getDistance(p1);
        boolean b = x.getDistance(p2) < d && x.getDistance(p1) < d;

        return b;
    }

    public boolean isSameSide(Point x) {
        return isOnline(x) && !isBetween(x);
    }

    public Point getMiddlePoint() {
        Point p = new Point();
        p.setX((p1.getX() + p2.getX()) / 2);
        p.setY((p1.getY() + p2.getY()) / 2);
        return p;
    }

    public Point getPointA() {
        return p1;
    }

    public Point getPointB() {
        return p2;
    }

    public double getAngle(Line l) {
        double k2 = getSlope();
        double k1 = l.getSlope();
        return (double) (Math.atan(Math.abs((k2 - k1) / (1 + k1 * k2))) * 180.0 / Math.PI);// 返回值为角度
    }

    public boolean isParallel(Line l) {
        Double b1 = this.getSlope();
        Double b2 = l.getSlope();
        if ((b1.isInfinite()) && (b2.isInfinite())) {
            return true;
        } else {
            return (this.getSlope().doubleValue() == l.getSlope().doubleValue());
        }
    }

    public boolean isCoincide(Line l) {
        if (!this.isParallel(l)) {
            return false;
        }
        if (this.isOnline(l.p1)) {
            return true;
        }
        return false;
    }

    public Point getIntersection(Line l) {
        // LineInputError.isParallelError(this, l);
        if (this.isParallel(l)) {
            return null;
        }
        if (p1.equals(l.p1) || p1.equals(l.p2)) {
            return p1;
        }
        if (p2.equals(l.p1) || p2.equals(l.p2)) {
            return p2;
        }
        Point p3 = l.p1, p4 = l.p2;
        double x_member, x_denominator, y_member, y_denominator;
        Point cross_point = new Point();
        x_denominator = p4.getX() * p2.getY() - p4.getX() * p1.getY() - p3.getX() * p2.getY() + p3.getX() * p1.getY() - p2.getX() * p4.getY() + p2.getX() * p3.getY() + p1.getX() * p4.getY()
                - p1.getX() * p3.getY();

        x_member = p3.getY() * p4.getX() * p2.getX() - p4.getY() * p3.getX() * p2.getX() - p3.getY() * p4.getX() * p1.getX() + p4.getY() * p3.getX() * p1.getX()
                - p1.getY() * p2.getX() * p4.getX() + p2.getY() * p1.getX() * p4.getX() + p1.getY() * p2.getX() * p3.getX() - p2.getY() * p1.getX() * p3.getX();

        if (x_denominator == 0)
            cross_point.setX(0);
        else
            cross_point.setX(x_member / x_denominator);

        y_denominator = p4.getY() * p2.getX() - p4.getY() * p1.getX() - p3.getY() * p2.getX() + p1.getX() * p3.getY() - p2.getY() * p4.getX() + p2.getY() * p3.getX() + p1.getY() * p4.getX()
                - p1.getY() * p3.getX();

        y_member = -p3.getY() * p4.getX() * p2.getY() + p4.getY() * p3.getX() * p2.getY() + p3.getY() * p4.getX() * p1.getY() - p4.getY() * p3.getX() * p1.getY()
                + p1.getY() * p2.getX() * p4.getY() - p1.getY() * p2.getX() * p3.getY() - p2.getY() * p1.getX() * p4.getY() + p2.getY() * p1.getX() * p3.getY();

        if (y_denominator == 0)
            cross_point.setY(0);
        else
            cross_point.setY(y_member / y_denominator);
        return cross_point; // 平行返回(0,0)
    }
}
class LineInputError {    
    public static void pointsCoincideError(Point p1, Point p2) {
        if ((p1.getX() == p2.getX()) && p1.getY() == p2.getY()) {
            System.out.println("points coincide");
            System.exit(0);
        }
    }
}
class OutFormat {
    public static Double doubleFormat(double b) {
        DecimalFormat df = new DecimalFormat("#.000");
        Double output = Double.valueOf(df.format(b));
        return output;
    }
}
 class ParseInput {
    public static void paseInput(String s, InputData d) {
        PointInputError.wrongChoice(s);        
        d.setChoice(getChoice(s));
        s = s.substring(2);
        pasePoints(s, d);
    }
    public static int getChoice(String s) {
        char c = s.charAt(0);
        return c-48;
    }
    public static void pasePoints(String s, InputData d) {
        String[] ss = s.split(" ");
        if (ss.length == 0)
            return;
        for (int i = 0; i < ss.length; i++) {
            d.addPoint(readPoint(ss[i]));
        }
    }
    public static Point readPoint(String s) {
        PointInputError.wrongPointFormat(s);
        String[] ss = s.split(",");
        double x = Double.parseDouble(ss[0]);
        double y = Double.parseDouble(ss[1]);
        return new Point(x, y);
    }
}
class Point {
    private double x;
    private double y;

    public Point(double x,double y) {
        this.x=x;
        this.y=y;
    }
    public Point() {
        
    }
    public void setX(double x) {
        this.x = x;
    }
    public void setY(double y) {
        this.y = y;
    }
    public double getX() {
        return x;
    }
    public double getY() {
        return y;
    }
    public boolean equals(Point p) {
        boolean b = false;
        if(this.x==p.getX()&&this.y==p.getY()) {
            b=true;
        }
        return b;
    }
    public double getDistance(Point p) {
        return Math.sqrt((x-p.getX()) * (x-p.getX())+(y-p.getY()) * (y-p.getY()));
    }
}
class PointInputError {
    public static void wrongNumberOfPoints(ArrayList ps, int num) {
        if (ps.size() != num) {
            System.out.println("wrong number of points");
            System.exit(0);
        }
    }
    public static void wrongPointFormat(String s) {
        if (!s.matches("[+-]?([1-9]\\d*|0)(\\.\\d+)?,[+-]?([1-9]\\d*|0)(\\.\\d+)?")) {
            System.out.println("Wrong Format");
            System.exit(0);
        }
    }
    public static void wrongChoice(String s) {
        if (!s.matches("[1-5]:.+")) {
            System.out.println("Wrong Format");
            System.exit(0);
        }
    }
    public static void Is_coincide_Points(ArrayList ps, int num) {
        if (ps.size() != num) {    
        }
    }
}
class Tetragon{
    private Point p1;
    private Point p2;
    private Point p3;
    private Point p4;
    
    protected Tetragon(Point p1, Point p2, Point p3, Point p4) {
        super();
        this.p1 = p1;
        this.p2 = p2;
        this.p3 = p3;
        this.p4 = p4;
    }

    public boolean isTetragon() {
        Line l1 = new Line(p1,p2);
        Line l2 = new Line(p2,p3);
        Line l3 = new Line(p3,p4);
        Line l4 = new Line(p4,p1);
        if(l1.isParallel(l2)||l2.isParallel(l3)||l3.isParallel(l4)||l4.isParallel(l1))
            return false;
        else if(l1.getIntersection(l3)!=null) {
            if(l1.isBetween(l1.getIntersection(l3))&& l3.isBetween(l1.getIntersection(l3))) {
                return false;
            }
            else {
                return true;
            }
        }else if(l2.getIntersection(l4)!=null) {
            if(l2.isBetween(l2.getIntersection(l4))&& l4.isBetween(l2.getIntersection(l4))) {
                return false;
            }
            else {
                return true;
            }
        }
        else
            return true;
    }

    public Triangle PointsisTriangle() {
        Line l1 = new Line(p1,p3);
        Line l2 = new Line(p2,p4);
        
        
        if(l1.getIntersection(l2).equals(p1)&&l2.isBetween(p1)) {
            Triangle t = new Triangle(p2,p3,p4);
            return t;
        }
        else if(l1.getIntersection(l2).equals(p2)&&l1.isBetween(p2)) {
            Triangle t = new Triangle(p1,p3,p4);
            return t;
        }
        else if(l1.getIntersection(l2).equals(p3)&&l2.isBetween(p3)) {
            Triangle t = new Triangle(p1,p2,p4);
            return t;
        }
        else if(l1.getIntersection(l2).equals(p4)&&l1.isBetween(p4)) {
            Triangle t = new Triangle(p1,p2,p3);
            return t;
        }
        else
            return null;
        
        
    }

    public double getArea() {
        Triangle t1 = new Triangle(p2,p3,p4);
        Triangle t2 = new Triangle(p1,p3,p4);
        Triangle t3 = new Triangle(p1,p2,p4);
        Triangle t4 = new Triangle(p1,p2,p3);
        
        if(IsConvex())
            return Math.abs(p1.getX() * p2.getY() + p2.getX() * p3.getY() + p3.getX() * p1.getY() - p1.getY() * p2.getX() - p2.getY() * p3.getX() - p3.getY() * p1.getX()) / 2.0+
                    Math.abs(p1.getX() * p4.getY() + p4.getX() * p3.getY() + p3.getX() * p1.getY() - p1.getY() * p4.getX() - p4.getY() * p3.getX() - p3.getY() * p1.getX()) / 2.0;
        else {
            if(t1.isInside(p1)==1||t3.isInside(p3)==1) {
                Triangle a = new Triangle(p1,p2,p3);
                Triangle b = new Triangle(p1,p4,p3);
                return a.getArea()+b.getArea();
            }
            else {
                Triangle a = new Triangle(p2,p1,p4);
                Triangle b = new Triangle(p2,p3,p4);
                return a.getArea()+b.getArea();
            }
        }
    }
    public double getPerimter() {
        Line l1 = new Line(p1,p2);
        Line l2 = new Line(p2,p3);
        Line l3 = new Line(p3,p4);
        Line l4 = new Line(p4,p1);
        return l1.getlength()+l2.getlength()+l3.getlength()+l4.getlength();
    }
    public boolean IsConvex() {
        Triangle a = new Triangle(p1,p2,p3);
        Triangle b = new Triangle(p3,p4,p1);
        Triangle c = new Triangle(p2,p3,p4);
        Triangle d = new Triangle(p4,p1,p2);
        if((a.getArea() + b.getArea()) == (c.getArea() + d.getArea()))
            return true;
        else
            return false;
    }
    public boolean IsParallelogram() {
        Line l1 = new Line(p1,p2);
        Line l2 = new Line(p2,p3);
        Line l3 = new Line(p3,p4);
        Line l4 = new Line(p4,p1);
        if((l1.getlength()==l3.getlength())&&l2.getlength()==l4.getlength()) {
            return true;
        }
        else
            return false;    
    }
    public boolean Isrhombus() {
        Line l1 = new Line(p1,p2);
        Line l2 = new Line(p2,p3);
        Line l3 = new Line(p3,p4);
        Line l4 = new Line(p4,p1);
        if(l1.getlength()==l2.getlength()&&l2.getlength()==l3.getlength()&&l3.getlength()==l4.getlength()) {
            return true;
        }
        else
            return false;
    }
    public boolean IsRectangle() {
        if(p1.getDistance(p3)==p2.getDistance(p4))
            return true;
        else
            return false;
    }

    public Point[] points() {
        if(p1.equals(p2)) {
            Point[] p = {p3,p4,p1};
            if((p3.getDistance(p4)+p3.getDistance(p1)>p4.getDistance(p1))&&(p3.getDistance(p4)-p3.getDistance(p1)<p4.getDistance(p1)))
                return p;
            else
                return null;
        }
        else if(p1.equals(p3)) {
            Point[] p = {p2,p4,p1};
            if((p2.getDistance(p4)+p2.getDistance(p1)>p4.getDistance(p1))&&(p2.getDistance(p4)-p2.getDistance(p1)<p4.getDistance(p1)))
                return p;
            else
                return null;
        }
        else if(p1.equals(p4)) {
            Point[] p = {p2,p3,p1};
            if((p2.getDistance(p3)+p2.getDistance(p1)>p3.getDistance(p1))&&(p2.getDistance(p1)-p2.getDistance(p1)<p3.getDistance(p1)))
                return p;
            else
                return null;
        }
        else if(p2.equals(p3)) {
            Point[] p = {p1,p4,p2};
            if((p1.getDistance(p4)+p1.getDistance(p2)>p4.getDistance(p2))&&(p1.getDistance(p4)-p1.getDistance(p2)<p4.getDistance(p2)))
                return p;
            else
                return null;
        }
        else if(p2.equals(p4)) {
            Point[] p = {p1,p3,p2};
            if((p1.getDistance(p3)+p1.getDistance(p2)>p3.getDistance(p2))&&(p1.getDistance(p3)-p1.getDistance(p2)<p3.getDistance(p2)))
                return p;
            else
                return null;
        }
        else if(p3.equals(p4)){
            Point[] p = {p1,p2,p3};
            if((p1.getDistance(p2)+p1.getDistance(p3)>p2.getDistance(p3))&&(p1.getDistance(p2)-p1.getDistance(p3)<p2.getDistance(p3)))
                return p;
            else
                return null;
        }
        else
            return null;
    }
        public boolean judgeLineCoincide(Line l) {
            Line l1 = new Line(p1,p2);
            Line l2 = new Line(p2,p3);
            Line l3 = new Line(p3,p4);
            Line l4 = new Line(p4,p1);
            
            if(l.isCoincide(l1)||l.isCoincide(l2)||l.isCoincide(l3)||l.isCoincide(l4)) {
                return true;
            }
            else
                return false;
        }
        public int isInside(Point p) {
            if (this.isOnTheEdge(p)) {
                return 0;
            }
            if (isVertex(p)) {
                return 0;
            }
            Triangle a =new Triangle(p, p1, p2);
            Triangle b =new Triangle(p, p2, p3);
            Triangle c =new Triangle(p, p3, p4);
            Triangle d =new Triangle(p, p1, p4);
            
            if(Math.abs(this.getArea() - a.getArea()-b.getArea()-c.getArea()-d.getArea() )< 1E-10) {
                return 1;
            }
            if(this.getArea() < a.getArea()+b.getArea()+c.getArea()+d.getArea()) {
                return -1;
            }
            return 0;
        }
        private boolean isVertex(Point p) {
                
            return p.equals(p1) || p.equals(p2) || p.equals(p3)|| p.equals(p4);
        }
        private boolean isOnTheEdge(Point p) {
            
            Line l1 = new Line(p1,p2);
            Line l2 = new Line(p2,p3);
            Line l3 = new Line(p3,p4);
            Line l4 = new Line(p4,p1);
            
            if(l1.isBetween(p)||l2.isBetween(p)||l3.isBetween(p)||l4.isBetween(p)) {
                return true;
            }
            else
                return false;
        }
}
class Triangle {
    private Point x;
    private Point y;
    private Point z;

    public Triangle(Point x, Point y, Point z) {
        this.x = x;
        this.y = y;
        this.z = z;
        if (!this.isTriangle()) {
            System.out.println("data error");
            System.exit(0);
        }
    }
    private boolean isTriangle() {
        if((x.getDistance(y)+x.getDistance(z)>y.getDistance(z))&&(x.getDistance(y)-x.getDistance(z)<y.getDistance(z)))
            return true;
        else
            return false;
    }
    public Point getMidpoint() {
        Point p = new Point();
        p.setX((this.x.getX() + this.y.getX() + this.z.getX()) / 3);
        p.setY((this.x.getY() + this.y.getY() + this.z.getY()) / 3);
        return p;
    }
    public Line[] getSideline() {
        Line line1 = new Line(x, y);
        Line line2 = new Line(x, z);
        Line line3 = new Line(y, z);

        Line[] lines = { line1, line2, line3 };
        return lines;
    }
    public double getArea() {
        double s = (x.getDistance(y) + y.getDistance(z) + z.getDistance(x))/2.0;
        return Math.sqrt(s * (s - x.getDistance(y)) * (s - y.getDistance(z)) * (s - z.getDistance(x)));
    }
    public double getPerimeter() {
        return x.getDistance(y) + y.getDistance(z) + z.getDistance(x);
    }

    public boolean isVertex(Point p) {
        return p.equals(x) || p.equals(y) || p.equals(z);
    }

    public int isInside(Point p) {
        if (this.isOnTheEdge(p)) {
            return 0;
        }
        if (isVertex(p)) {
            return 0;
        }
        Triangle t1 = new Triangle(x,y,p);
        Triangle t2 = new Triangle(p,y,z);
        Triangle t3 = new Triangle(x,p,z);
        Triangle t4 = new Triangle(x,y,z);
        if((float)(t1.getArea()+t2.getArea()+t3.getArea())==(float)(t4.getArea())) {
            return 1;
        }
        else {
            return -1;
        }
    }
    public ArrayList<Point> getIntersections(Line l) {
        ArrayList<Point> p = new ArrayList<Point> ();
        Line a = new Line(x,y);
        Line b = new Line(y,z);
        Line c = new Line(x,z);
        if(l.getIntersection(a).equals(l.getIntersection(b))&&l.getIntersection(a)!=null){
            p.add(l.getIntersection(a));
            if(l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c)))
                p.add(l.getIntersection(c));
            return p;
        }
        else if(l.getIntersection(b).equals(l.getIntersection(c))&&l.getIntersection(b)!=null) {
            p.add(l.getIntersection(b));
            if(l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))) {
                p.add(l.getIntersection(a));
            }
            return p;
        }else if(l.getIntersection(c).equals(l.getIntersection(a))&&l.getIntersection(c)!=null) {
            p.add(l.getIntersection(c));
            if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
                p.add(l.getIntersection(b));
            }
            return p;
        }
            
        if(l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))) {
            p.add(l.getIntersection(a));
        }
        if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
            p.add(l.getIntersection(b));
        }
        if(l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c)))
            p.add(l.getIntersection(c));
        return p;
    }
     public double[] calArea(Point p1, Point p2) {
         Line L = new Line(p1,p2);
         Line a = new Line(y,z);
         Line b = new Line(x,z);
         Line c = new Line(x,y);
         Triangle t;
         Tetragon tet;
         
         if((L.getIntersection(a)!=null&&L.getIntersection(b)!=null)) {
             if((L.getIntersection(a).equals(p1)&&L.getIntersection(b).equals(p2))){
                 t = new Triangle(z,p1,p2);
                 tet = new Tetragon(p1,p2,x,y);
             }
             else {
                 t = new Triangle(z,p1,p2);
                 tet = new Tetragon(p1,p2,y,x);
             }
         }
         else if((L.getIntersection(a)!=null&&L.getIntersection(c)!=null)) {
             if((L.getIntersection(a).equals(p1)&&L.getIntersection(c).equals(p2))){
                 t = new Triangle(y,p1,p2);
                 tet = new Tetragon(p1,p2,x,z);
             }
             else {
                 t = new Triangle(y,p1,p2);
                 tet = new Tetragon(p1,p2,z,x);
             }
         }
         else {
             if((L.getIntersection(b).equals(p1)&&L.getIntersection(c).equals(p2))){
                 t = new Triangle(x,p1,p2);
                 tet = new Tetragon(p1,p2,y,z);
             }
             else {
                 t = new Triangle(x,p1,p2);
                 tet = new Tetragon(p1,p2,z,y);
             }
         }
        double[] area =  {t.getArea(),tet.getArea()};
        if(area[0]>area[1]) {
            double m=0;
            m=area[0];
            area[0]=area[1];
            area[1]=m;
        }
        return area;
    }
     public double[] calTriangleArea(Point p1, Point p2) {
         Triangle t1;
         Triangle t2;
         if(p1.equals(x)) {
             t1 = new Triangle(p1,p2,y);
             t2 = new Triangle(p1,p2,z);
         }
         else if(p1.equals(y )) {
             t1 = new Triangle(p1,p2,x);
             t2 = new Triangle(p1,p2,z);
         }
         else {
             t1 = new Triangle(p1,p2,x);
             t2 = new Triangle(p1,p2,y);
         }     
         double[] area =  {t1.getArea(),t2.getArea()};
            if(area[0]>area[1]) {
                double m=0;
                m=area[0];
                area[0]=area[1];
                area[1]=m;
            }
            return area;
     }
    public double calAreaDiffrence(Triangle t1) {
        double area = t1.getArea();
        area = getArea() - area;
        return area;
    }
    public boolean judgeLineCoincide(Line l) {
        Line l1 = new Line(x,y);
        Line l2 = new Line(y,z);
        Line l3 = new Line(z,x);
        
        if(l.isCoincide(l1)||l.isCoincide(l2)||l.isCoincide(l3)) {
            return true;
        }
        else
            return false;
    }
    public boolean isOnTheEdge(Point p) {
        Line l1 = new Line(x,y);
        Line l2 = new Line(y,z);
        Line l3 = new Line(z,x);
        
        if(l1.isBetween(p)||l2.isBetween(p)||l3.isBetween(p)) {
            return true;
        }
        else
            return false;
    }

    public Point getX() {
        return x;
    }
    public void setX(Point x) {
        this.x = x;
    }
    public Point getY() {
        return y;
    }
    public void setY(Point y) {
        this.y = y;
    }
    public Point getZ() {
        return z;
    }
    public void setZ(Point z) {
        this.z = z;
    }
}

下面讲讲选项五，输入六个点的坐标，然后前两个点构成一条直线，再判断后四个点能否构成四边形，若构成四边形则用找到直线与四边形的交点，若交点为两个则输出分割成两部分的面积，若交点为1或0则直接输出。若构不成四边形则判断四个点能否构成三角形，能则找出面积最大的那个，再找交点、输出面积。既不是四边形也不是三角形则输出构不成多边形。详细的我将在后面的题目仔细介绍。

 

　　3、第三题没什么 难点，只要按题目要求输出特定的东西。

+ View Code?

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import java.util.Scanner;   public class BankBusiness {           public static String bankName="中国银行";     private String name;     private String passward;     private double ballence;     Scanner input = new Scanner(System.in);                 protected BankBusiness(String name, String passward) {         super();         this.name = name;         this.passward = passward;         this.ballence = 0;     }           public static void welcome() {         System.out.println(bankName+"欢迎您的到来！");     }           public static void welcomeNext() {         System.out.println("请收好您的证件和物品，欢迎您下次光临！");     }           public void deposit() {         String s =input.nextLine();         String[] tokens = s.split("[\\s]");         String PassWard=tokens[0];         if(judge(PassWard))         {             ballence=Double.parseDouble(tokens[1]);             System.out.println("您的余额有"+ballence+"元。");         }         else             System.out.println("您的密码错误！");     }           public void withdraw() {         double money;         String s =input.nextLine();         String[] tokens = s.split("[\\s]");         String PassWard=tokens[0];         money=Double.parseDouble(tokens[1]);         if(judge(PassWard)) {             handle(money);         }         else             System.out.println("您的密码错误！");     }           public boolean judge(String PassWard) {         if(passward.equals(PassWard))             return true;         else             return false;     }           public void handle(double money) {         if(money<=ballence) {             ballence-=money;             System.out.println("请取走钞票，您的余额还有"+ballence+"元。");         }         else             System.out.println("您的余额不足！");     } }

 

（2）期中考试题目设计与分析

　　期中考试的试题考察的就是类的设计和继承和多态的运用，难度不大，只需按照题目要求来即可，唯一可能算难点的便是父类的创建，里面需要用到许多的容器函数。

+ View Code?

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import java.util.ArrayList;   public class GeometryObject {           ArrayList<Element> element = new ArrayList<Element>();           public void add(Element e) {         element.add(e);     }           public void remove(int i) {         element.remove(i);     }           public ArrayList<Element> getList() {         return element;     }   }

　　

（3）第五次作业设计与分析

这一题也是建立在前几次作业的基础上考察五边形的相关问题。

选项一和选项二比较简单分别需要完成对五边形的判断和凹凸性的判断，计算方面就是计算五边形面积和周长

 

五边形的判断：

+ View Code?

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public boolean IsPentagon() {         Line l1 = new Line(p1,p2);         Line l2 = new Line(p2,p3);         Line l3 = new Line(p3,p4);         Line l4 = new Line(p4,p5);         Line l5 = new Line(p5,p1);                   if(l1.isParallel(l2)||l2.isParallel(l3)||l3.isParallel(l4)||l4.isParallel(l5)||l5.isParallel(l1))             return false;                   if((l1.getIntersection(l3) != null && l1.isBetween(l1.getIntersection(l3)) && l3.isBetween(l1.getIntersection(l3)))                 || (l1.getIntersection(l4) != null && l1.isBetween(l1.getIntersection(l4)) && l4.isBetween(l1.getIntersection(l4)))                 || (l2.getIntersection(l4) != null && l2.isBetween(l2.getIntersection(l4)) && l4.isBetween(l2.getIntersection(l4)))                 || (l2.getIntersection(l5) != null && l2.isBetween(l2.getIntersection(l5)) && l5.isBetween(l2.getIntersection(l5)))                 || (l3.getIntersection(l5) != null && l3.isBetween(l3.getIntersection(l5)) && l5.isBetween(l3.getIntersection(l5)))                 || l1.isBetween(p4) || l2.isBetween(p5) || l3.isBetween(p1) || l4.isBetween(p2) || l5.isBetween(p3)){             //相隔一条线的两条线没有交点             return false;         }         else {             return true;         }                    }

　凹凸性的判断就是运用向量叉乘，如果是凸的，那必然任意两条线的方向向量叉乘的符号必然相同，并且我们可以用点来代表向量

+ View Code?

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public boolean IsTuPentagon() {         Point a = new Point(p2.getX()-p1.getX(), p2.getY()-p1.getY());         Point b = new Point(p3.getX()-p2.getX(), p3.getY()-p2.getY());         Point c = new Point(p4.getX()-p3.getX(), p4.getY()-p3.getY());         Point d = new Point(p5.getX()-p4.getX(), p5.getY()-p4.getY());         Point e = new Point(p1.getX()-p5.getX(), p1.getY()-p5.getY());                   double[] crossProduct = new double[5];                   crossProduct[0]=a.getX()*b.getY()-a.getY()*b.getX();         crossProduct[1]=b.getX()*c.getY()-b.getY()*c.getX();         crossProduct[2]=c.getX()*d.getY()-c.getY()*d.getX();         crossProduct[3]=d.getX()*e.getY()-d.getY()*e.getX();         crossProduct[4]=e.getX()*a.getY()-e.getY()*a.getX();                             if(crossProduct[0]*crossProduct[1]<0||crossProduct[0]*crossProduct[2]<0||crossProduct[0]*crossProduct[3]<0) {             return false;         }         else             return true;     }

　面积和周长比较简单，面积只需要将五边形切割成三角形或者四边形即可。

 

选项三：

　　题目：输入七个点坐标，前两个点构成一条直线，后五个点构成一个凸五边形、凸四边形或凸三角形，输出直线与五边形、四边形或三角形相交的交点数量。如果交点有两个，再按面积从小到大输出被直线分割成两部分的面积（不换行）。若直线与多边形形的一条边线重合，输出"The line is coincide with one of the lines"。若后五个点不符合五边形输入，若前两点重合，输出"points coincide"。

首先我们的思路就是先判断它是否为五边形，不是五边形则再判断是否为四边形，还不是那再判断是否为三角形，是对应的图形则再去找交点，并且判断焦点数量，再输出判断好大小的两部分的面积。

找线与五边形的焦点：

public ArrayList<Point> getIntersections(Line l){
        ArrayList<Point> p = new ArrayList<Point> ();
        Line a = new Line(p1,p2);
        Line b = new Line(p2,p3);
        Line c = new Line(p3,p4);
        Line d = new Line(p4,p5);
        Line e = new Line(p5,p1);
        
        if(l.getIntersection(e)!=null&&l.getIntersection(a)!=null&&l.getIntersection(e).equals(l.getIntersection(a))) {
            p.add(l.getIntersection(e));
            if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c)))
                p.add(l.getIntersection(b));
            else if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d)))
                p.add(l.getIntersection(d));
            else if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
                p.add(l.getIntersection(c));
            else if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
                p.add(l.getIntersection(b));
            else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
                p.add(l.getIntersection(d));
            return p;    
        }
        else if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b))) {
            p.add(l.getIntersection(a));
            if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d)))
                p.add(l.getIntersection(c));
            else if(l.getIntersection(d)!=null&&l.getIntersection(e)!=null&&l.getIntersection(d).equals(l.getIntersection(e)))
                p.add(l.getIntersection(d));
            else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
                p.add(l.getIntersection(d));
            else if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
                p.add(l.getIntersection(c));
            else if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
                p.add(l.getIntersection(e));
            return p;    
        }
        else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c))) {
            p.add(l.getIntersection(b));
            if(l.getIntersection(e)!=null&&l.getIntersection(d)!=null&&l.getIntersection(e).equals(l.getIntersection(d)))
                p.add(l.getIntersection(d));
            else if(l.getIntersection(a)!=null&&l.getIntersection(e)!=null&&l.getIntersection(a).equals(l.getIntersection(e)))
                p.add(l.getIntersection(a));
            else if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
                p.add(l.getIntersection(e));
            else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
                p.add(l.getIntersection(a));
            else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
                p.add(l.getIntersection(d));
            return p;    
        }
        else if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d))) {
            p.add(l.getIntersection(c));
            if(l.getIntersection(e)!=null&&l.getIntersection(a)!=null&&l.getIntersection(e).equals(l.getIntersection(a)))
                p.add(l.getIntersection(e));
            else if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b)))
                p.add(l.getIntersection(a));
            else if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
                p.add(l.getIntersection(e));
            else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
                p.add(l.getIntersection(a));
            else if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
                p.add(l.getIntersection(b));
            return p;    
        }
        else if(l.getIntersection(e)!=null&&l.getIntersection(d)!=null&&l.getIntersection(e).equals(l.getIntersection(d))) {
            p.add(l.getIntersection(d));
            if(l.getIntersection(b)!=null&&l.getIntersection(a)!=null&&l.getIntersection(b).equals(l.getIntersection(a)))
                p.add(l.getIntersection(b));
            else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c)))
                p.add(l.getIntersection(c));
            else if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
                p.add(l.getIntersection(c));
            else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
                p.add(l.getIntersection(a));
            else if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
                p.add(l.getIntersection(b));
            return p;    
        }
        
        if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
            p.add(l.getIntersection(a));
        if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
            p.add(l.getIntersection(b));
        if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
            p.add(l.getIntersection(c));
        if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
            p.add(l.getIntersection(d));
        if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
            p.add(l.getIntersection(e));
        
        return p;
        
    }

将焦点传入，计算两部分的面积并传出：

public double[] calPentagonArea(Point x, Point y) {
        Line a = new Line(p1,p2);
        Line b = new Line(p2,p3);
        Line c = new Line(p3,p4);
        Line d = new Line(p4,p5);
        Line e = new Line(p5,p1);
        
        double[] area =  new double[2];
        
        if(x.equals(p1)) {
            if(y.equals(p3)) {
                Triangle t1 = new Triangle(x,y,p2);
                Tetragon t2 = new Tetragon(x,y,p4,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(y.equals(p4)) {
                Triangle t1 = new Triangle(x,y,p5);
                Tetragon t2 = new Tetragon(x,y,p3,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(b.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p2);
                Pentagon t2 = new Pentagon(x,y,p3,p4,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(c.isBetween(y)) {
                Tetragon t1 = new Tetragon(x,y,p3,p2);
                Tetragon t2 = new Tetragon(x,y,p4,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p5);
                Pentagon t2 = new Pentagon(x,y,p4,p3,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }    
        }
        else if(x.equals(p2)) {
            if(y.equals(p4)) {
                Triangle t1 = new Triangle(x,y,p3);
                Tetragon t2 = new Tetragon(x,y,p5,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(y.equals(p5)) {
                Triangle t1 = new Triangle(x,y,p1);
                Tetragon t2 = new Tetragon(x,y,p4,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(c.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p3);
                Pentagon t2 = new Pentagon(x,y,p4,p5,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(d.isBetween(y)) {
                Tetragon t1 = new Tetragon(x,y,p4,p3);
                Tetragon t2 = new Tetragon(x,y,p5,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p1);
                Pentagon t2 = new Pentagon(x,y,p5,p4,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
        }
        else if(x.equals(p3)) {
            if(y.equals(p5)) {
                Triangle t1 = new Triangle(x,y,p4);
                Tetragon t2 = new Tetragon(x,y,p1,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(y.equals(p1)) {
                Triangle t1 = new Triangle(x,y,p2);
                Tetragon t2 = new Tetragon(x,y,p5,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(d.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p4);
                Pentagon t2 = new Pentagon(x,y,p5,p1,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(e.isBetween(y)) {
                Tetragon t1 = new Tetragon(x,y,p5,p4);
                Tetragon t2 = new Tetragon(x,y,p1,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p2);
                Pentagon t2 = new Pentagon(x,y,p1,p5,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
        }
        else if(x.equals(p4)) {
            if(y.equals(p1)) {
                Triangle t1 = new Triangle(x,y,p5);
                Tetragon t2 = new Tetragon(x,y,p2,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(y.equals(p2)) {
                Triangle t1 = new Triangle(x,y,p3);
                Tetragon t2 = new Tetragon(x,y,p1,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(e.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p5);
                Pentagon t2 = new Pentagon(x,y,p1,p2,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(a.isBetween(y)) {
                Tetragon t1 = new Tetragon(x,y,p1,p5);
                Tetragon t2 = new Tetragon(x,y,p2,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p3);
                Pentagon t2 = new Pentagon(x,y,p2,p1,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
        }
        else if(x.equals(p5)) {
            if(y.equals(p2)) {
                Triangle t1 = new Triangle(x,y,p1);
                Tetragon t2 = new Tetragon(x,y,p3,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(y.equals(p3)) {
                Triangle t1 = new Triangle(x,y,p4);
                Tetragon t2 = new Tetragon(x,y,p2,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(a.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p1);
                Pentagon t2 = new Pentagon(x,y,p2,p3,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else if(b.isBetween(y)) {
                Tetragon t1 = new Tetragon(x,y,p2,p1);
                Tetragon t2 = new Tetragon(x,y,p3,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p4);
                Pentagon t2 = new Pentagon(x,y,p3,p2,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea();
            }
        }
        else if((a.isBetween(x)&&e.isBetween(y))||(a.isBetween(y)&&e.isBetween(x))) {
            if(a.isBetween(y)&&e.isBetween(x)) {
                Triangle t1 = new Triangle(x,y,p1);
                Tetragon t2 = new Tetragon(x,y,p2,p5);
                Tetragon t3 = new Tetragon(p2,p3,p4,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p1);
                Tetragon t2 = new Tetragon(x,y,p5,p2);
                Tetragon t3 = new Tetragon(p2,p3,p4,p5);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
        }
        else if((a.isBetween(x)&&b.isBetween(y))||(a.isBetween(y)&&b.isBetween(x))) {
            if(a.isBetween(x)&&b.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p2);
                Tetragon t2 = new Tetragon(x,y,p3,p1);
                Tetragon t3 = new Tetragon(p3,p4,p5,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p1);
                Tetragon t2 = new Tetragon(x,y,p1,p3);
                Tetragon t3 = new Tetragon(p3,p4,p5,p1);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
        }
        else if((b.isBetween(x)&&c.isBetween(y))||(b.isBetween(y)&&c.isBetween(x))) {
            if(b.isBetween(x)&&c.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p3);
                Tetragon t2 = new Tetragon(x,y,p4,p2);
                Tetragon t3 = new Tetragon(p4,p5,p1,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p3);
                Tetragon t2 = new Tetragon(x,y,p2,p4);
                Tetragon t3 = new Tetragon(p4,p5,p1,p2);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
        }
        else if((c.isBetween(x)&&d.isBetween(y))||(c.isBetween(y)&&d.isBetween(x))) {
            if(c.isBetween(x)&&d.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p4);
                Tetragon t2 = new Tetragon(x,y,p5,p3);
                Tetragon t3 = new Tetragon(p5,p1,p2,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p4);
                Tetragon t2 = new Tetragon(x,y,p3,p5);
                Tetragon t3 = new Tetragon(p5,p1,p2,p3);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
        }
        else {
            if(d.isBetween(x)&&e.isBetween(y)) {
                Triangle t1 = new Triangle(x,y,p5);
                Tetragon t2 = new Tetragon(x,y,p1,p4);
                Tetragon t3 = new Tetragon(p1,p2,p3,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
            else {
                Triangle t1 = new Triangle(x,y,p5);
                Tetragon t2 = new Tetragon(x,y,p4,p1);
                Tetragon t3 = new Tetragon(p1,p2,p3,p4);
                area[0] = t1.getArea();
                area[1] = t2.getArea()+t3.getArea();
            }
        }
        
        if(area[0]>area[1]) {
            double m=0;
            m=area[0];
            area[0]=area[1];
            area[1]=m;
        }
        return area;
    }

 

判断五个点是否构成四边形：

/* 判断p1\p2\p3\p4\P5五个点的坐标是否能构成一个四边形 */
    public Tetragon PointsisTetragon() {
        Tetragon t1 = new Tetragon(p2,p3,p4,p5);
        Tetragon t2 = new Tetragon(p1,p3,p4,p5);
        Tetragon t3 = new Tetragon(p1,p2,p4,p5);
        Tetragon t4 = new Tetragon(p1,p2,p3,p5);
        Tetragon t5 = new Tetragon(p1,p2,p3,p4);
        Line l1 = new Line(p2,p5);
        Line l2 = new Line(p1,p3);
        Line l3 = new Line(p2,p4);
        Line l4 = new Line(p3,p5);
        Line l5 = new Line(p1,p4);
        
        if(p1.equals(p2)||p1.equals(p3)||p1.equals(p4)||p1.equals(p5)||l1.isBetween(p1))
            return t1;
        else if(p2.equals(p1)||p2.equals(p3)||p2.equals(p4)||p2.equals(p5)||l2.isBetween(p2))
            return t2;
        else if(p3.equals(p1)||p3.equals(p2)||p3.equals(p4)||p3.equals(p5)||l3.isBetween(p3))
            return t3;
        else if(p4.equals(p1)||p4.equals(p2)||p4.equals(p3)||p4.equals(p5)||l4.isBetween(p4))
            return t4;
        else if(p5.equals(p1)||p5.equals(p2)||p5.equals(p3)||p5.equals(p5)||l5.isBetween(p5))
            return t5;
        else
            return null;
    }

找线与四边形的焦点：

// 获取直线l与四边形的交点，如果没有，数组为空。
        public ArrayList<Point> getIntersections(Line l) {
            ArrayList<Point> p = new ArrayList<Point> ();
            Line a = new Line(p1,p2);
            Line b = new Line(p2,p3);
            Line c = new Line(p3,p4);
            Line d = new Line(p4,p1);
            if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b))){
                p.add(l.getIntersection(a));
                if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
                    p.add(l.getIntersection(c));
                else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
                    p.add(l.getIntersection(d));
                else if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d)))
                    p.add(l.getIntersection(c));
                return p;
            }
            else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c))) {
                p.add(l.getIntersection(b));
                if(l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))) {
                    p.add(l.getIntersection(a));    
                }
                else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
                    p.add(l.getIntersection(d));
                else if(l.getIntersection(a)!=null&&l.getIntersection(d)!=null&&l.getIntersection(a).equals(l.getIntersection(d)))
                    p.add(l.getIntersection(a));
                return p;
            }else if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d))) {
                p.add(l.getIntersection(c));
                if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
                    p.add(l.getIntersection(b));
                }
                else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
                    p.add(l.getIntersection(a));
                else if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b)))
                    p.add(l.getIntersection(a));
                return p;
            }
            else if(l.getIntersection(d)!=null&&l.getIntersection(a)!=null&&l.getIntersection(d).equals(l.getIntersection(a))) {
                p.add(l.getIntersection(c));
                if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
                    p.add(l.getIntersection(b));
                }
                else if((l.getIntersection(c)!=null&&a.isBetween(l.getIntersection(c))))
                    p.add(l.getIntersection(c));
                else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c)))
                    p.add(l.getIntersection(b));
                return p;
            }
            
            if(l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))) {
                p.add(l.getIntersection(a));
            }
            
            if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
                p.add(l.getIntersection(b));
            }
            
            if(l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))) {
                p.add(l.getIntersection(c));
            }
            
            if(l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))) {
                p.add(l.getIntersection(d));
            }
            
            return p;
        }

将焦点传入，输出将四边形分割成两部分的面积并排序：

public double[] calTetragonArea(Point x, Point y) {
            Line a = new Line(p1,p2);
            Line b = new Line(p2,p3);
            Line c = new Line(p3,p4);
            Line d = new Line(p4,p1);
            double[] area =  new double[2];
            
            if(p1.equals(x)) {
                if(b.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p3,p4);
                    Triangle t2 = new Triangle(p2,x,y);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(c.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p3,p2);
                    Triangle t2 = new Triangle(p4,x,y);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p1,p2,p3);
                    Triangle t2 = new Triangle(p1,p3,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }
            else if(p2.equals(x)) {
                if(c.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p4,p1);
                    Triangle t2 = new Triangle(x,y,p3);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(d.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p4,p3);
                    Triangle t2 = new Triangle(x,y,p1);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p1,p2,p4);
                    Triangle t2 = new Triangle(p3,p2,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }
            else if(p3.equals(x)) {
                if(a.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p1,p4);
                    Triangle t2 = new Triangle(x,y,p2);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(d.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p1,p2);
                    Triangle t2 = new Triangle(x,y,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p1,p2,p3);
                    Triangle t2 = new Triangle(p1,p3,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }
            else if(p4.equals(x)) {
                if(a.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p2,p3);
                    Triangle t2 = new Triangle(p1,x,y);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(b.isBetween(y)) {
                    Tetragon t1 = new Tetragon(p1,p2,y,x);
                    Triangle t2 = new Triangle(p3,x,y);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p1,p2,p4);
                    Triangle t2 = new Triangle(p3,p2,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }else if(a.isBetween(x)) {
                if(b.isBetween(y)) {
                    Triangle t1 = new Triangle(p2,x,y);
                    Pentagon t2 = new Pentagon(x,y,p3,p4,p1);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(c.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p4,p1);
                    Tetragon t2 = new Tetragon(x,y,p3,p2);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p1,x,y);
                    Pentagon t2 = new Pentagon(x,y,p4,p3,p2);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }else if(b.isBetween(x)) {
                if(a.isBetween(y)) {
                    Triangle t1 = new Triangle(p2,x,y);
                    Pentagon t2 = new Pentagon(x,y,p1,p4,p3);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(d.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p4,p3);
                    Tetragon t2 = new Tetragon(x,y,p1,p2);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p3,x,y);
                    Pentagon t2 = new Pentagon(x,y,p4,p1,p2);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }else if(c.isBetween(x)) {
                if(b.isBetween(y)) {
                    Triangle t1 = new Triangle(p3,x,y);
                    Pentagon t2 = new Pentagon(x,y,p2,p1,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(a.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p2,p3);
                    Tetragon t2 = new Tetragon(x,y,p1,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p4,x,y);
                    Pentagon t2 = new Pentagon(x,y,p1,p2,p3);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }else {
                if(c.isBetween(y)) {
                    Triangle t1 = new Triangle(p4,x,y);
                    Pentagon t2 = new Pentagon(x,y,p3,p2,p1);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else if(b.isBetween(y)) {
                    Tetragon t1 = new Tetragon(x,y,p2,p1);
                    Tetragon t2 = new Tetragon(x,y,p3,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
                else {
                    Triangle t1 = new Triangle(p1,x,y);
                    Pentagon t2 = new Pentagon(x,y,p2,p3,p4);
                    area[0] = t1.getArea();
                    area[1] = t2.getArea();
                }
            }

            if(area[0]>area[1]) {
                double m=0;
                m=area[0];
                area[0]=area[1];
                area[1]=m;
            }
            return area;
        }

 

判断四个点能否构成三角形：

/* 判断四个点点的坐标是否能构成一个三角形 */
    public Triangle PointsisTriangle() {
        Line l1 = new Line(p1,p3);
        Line l2 = new Line(p2,p4);
        
        
        if(l1.getIntersection(l2).equals(p1)&&l2.isBetween(p1)) {
            Triangle t = new Triangle(p2,p3,p4);
            return t;
        }
        else if(l1.getIntersection(l2).equals(p2)&&l1.isBetween(p2)) {
            Triangle t = new Triangle(p1,p3,p4);
            return t;
        }
        else if(l1.getIntersection(l2).equals(p3)&&l2.isBetween(p3)) {
            Triangle t = new Triangle(p1,p2,p4);
            return t;
        }
        else if(l1.getIntersection(l2).equals(p4)&&l1.isBetween(p4)) {
            Triangle t = new Triangle(p1,p2,p3);
            return t;
        }
        else
            return null;
        
        
    }

找线与三角形的焦点：

    // 获取直线l与三角形的交点，如果没有，数组为空。
    public ArrayList<Point> getIntersections(Line l) {
        ArrayList<Point> p = new ArrayList<Point> ();
        Line a = new Line(x,y);
        Line b = new Line(y,z);
        Line c = new Line(x,z);
        if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b))){
            p.add(l.getIntersection(a));
            if(l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c)))
                p.add(l.getIntersection(c));
            return p;
        }
        else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c))) {
            p.add(l.getIntersection(b));
            if(l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))) {
                p.add(l.getIntersection(a));
            }
            return p;
        }else if(l.getIntersection(c)!=null&&l.getIntersection(a)!=null&&l.getIntersection(c).equals(l.getIntersection(a))) {
            p.add(l.getIntersection(c));
            if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
                p.add(l.getIntersection(b));
            }
            return p;
        }
            
        if(l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))) {
            p.add(l.getIntersection(a));
        }
        if(l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))) {
            p.add(l.getIntersection(b));
        }
        if(l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c)))
            p.add(l.getIntersection(c));
        return p;
    }

将焦点传入，计算将三角形分割成两部分的面积：

public double[] calTriangleArea(Point p1, Point p2) {
         Triangle t1;
         Triangle t2;
         Triangle[] a = new Triangle[3];
         Tetragon[] b = new Tetragon[3];
         
         if(p1.equals(x)||p1.equals(y)||p1.equals(z)||p2.equals(x)||p2.equals(y)||p2.equals(z)) {
             if(p1.equals(x)||p2.equals(x)) {
                 t1 = new Triangle(p1,p2,y);
                 t2 = new Triangle(p1,p2,z);
             }
             else if(p1.equals(y)||p2.equals(y)) {
                 t1 = new Triangle(p1,p2,x);
                 t2 = new Triangle(p1,p2,z);
             }
             else {
                 t1 = new Triangle(p1,p2,x);
                 t2 = new Triangle(p1,p2,y);
             }
                 
             double[] area =  {t1.getArea(),t2.getArea()};
                if(area[0]>area[1]) {
                    double m=0;
                    m=area[0];
                    area[0]=area[1];
                    area[1]=m;
                }
                return area;
         }
         else {
             a[0] = new Triangle(p1,p2,x);
             a[1] = new Triangle(p1,p2,y);
             a[2] = new Triangle(p1,p2,z);
             b[0] = new Tetragon(p1,p2,y,z);
             b[1] = new Tetragon(p1,p2,x,z);
             b[2] = new Tetragon(p1,p2,x,y);
             
             if(this.getArea()-(a[0].getArea()+b[0].getArea())<0.00001) {
                 double[] area =  {a[0].getArea(),b[0].getArea()};
                    if(area[0]>area[1]) {
                        double m=0;
                        m=area[0];
                        area[0]=area[1];
                        area[1]=m;
                    }
                    return area;
             }
             else if(this.getArea()-(a[1].getArea()+b[1].getArea())<0.00001) {
                 double[] area =  {a[1].getArea(),b[1].getArea()};
                    if(area[0]>area[1]) {
                        double m=0;
                        m=area[0];
                        area[0]=area[1];
                        area[1]=m;
                    }
                    return area;
             }
             else {
                 double[] area =  {a[2].getArea(),b[2].getArea()};
                    if(area[0]>area[1]) {
                        double m=0;
                        m=area[0];
                        area[0]=area[1];
                        area[1]=m;
                    }
                    return area;
             }
             
         }
        
     }

 

选项四：

任然需要用到选项三判断五个点构成什么图形的方法，然后在判断两图形的关系

 

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

public Point[] points() {         Line[] L = new Line[6];         L[0] = new Line(p1,p2);         L[1] = new Line(p1,p3);         L[2] = new Line(p1,p4);         L[3] = new Line(p1,p5);         L[4] = new Line(p2,p3);         L[5] = new Line(p2,p4);         L[6] = new Line(p2,p5);         L[7] = new Line(p3,p4);         L[8] = new Line(p3,p5);         L[9] = new Line(p4,p5);                   if(L[6].isBetween(p1)||p1.equals(p2)||p1.equals(p5)) {             Point[] p = {p2,p3,p4,p5};             return p;         }                   if(L[1].isBetween(p2)||p2.equals(p1)||p2.equals(p3)) {             Point[] p = {p1,p3,p4,p5};             return p;         }                   if(L[5].isBetween(p3)||p3.equals(p2)||p3.equals(p4)) {             Point[] p = {p1,p2,p4,p5};             return p;         }                   if(L[2].isBetween(p5)||p5.equals(p4)||p5.equals(p1)) {             Point[] p = {p1,p2,p3,p4};             return p;         }                   if(L[8].isBetween(p5)||p4.equals(p3)||p4.equals(p5)) {             Point[] p = {p1,p2,p3,p5};             return p;         }                   return null;     }

　　

　　

选项五 ：

找焦点

 

选项六：

 运用面积法，即判断点与其他点构成的图形的面积之和是否等于整个图形的面积，若等于，则说明在图形内部，在判断点是否在线或者端点上，若都不是，则是在图形外。

 

public ArrayList<Point> getIntersections(Line l){
ArrayList<Point> p = new ArrayList<Point> ();
Line a = new Line(p1,p2);
Line b = new Line(p2,p3);
Line c = new Line(p3,p4);
Line d = new Line(p4,p5);
Line e = new Line(p5,p1);

if(l.getIntersection(e)!=null&&l.getIntersection(a)!=null&&l.getIntersection(e).equals(l.getIntersection(a))) {
p.add(l.getIntersection(e));
if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c)))
p.add(l.getIntersection(b));
else if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d)))
p.add(l.getIntersection(d));
else if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
p.add(l.getIntersection(c));
else if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
p.add(l.getIntersection(b));
else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
p.add(l.getIntersection(d));
return p;
}
else if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b))) {
p.add(l.getIntersection(a));
if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d)))
p.add(l.getIntersection(c));
else if(l.getIntersection(d)!=null&&l.getIntersection(e)!=null&&l.getIntersection(d).equals(l.getIntersection(e)))
p.add(l.getIntersection(d));
else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
p.add(l.getIntersection(d));
else if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
p.add(l.getIntersection(c));
else if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
p.add(l.getIntersection(e));
return p;
}
else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c))) {
p.add(l.getIntersection(b));
if(l.getIntersection(e)!=null&&l.getIntersection(d)!=null&&l.getIntersection(e).equals(l.getIntersection(d)))
p.add(l.getIntersection(d));
else if(l.getIntersection(a)!=null&&l.getIntersection(e)!=null&&l.getIntersection(a).equals(l.getIntersection(e)))
p.add(l.getIntersection(a));
else if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
p.add(l.getIntersection(e));
else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
p.add(l.getIntersection(a));
else if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
p.add(l.getIntersection(d));
return p;
}
else if(l.getIntersection(c)!=null&&l.getIntersection(d)!=null&&l.getIntersection(c).equals(l.getIntersection(d))) {
p.add(l.getIntersection(c));
if(l.getIntersection(e)!=null&&l.getIntersection(a)!=null&&l.getIntersection(e).equals(l.getIntersection(a)))
p.add(l.getIntersection(e));
else if(l.getIntersection(a)!=null&&l.getIntersection(b)!=null&&l.getIntersection(a).equals(l.getIntersection(b)))
p.add(l.getIntersection(a));
else if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
p.add(l.getIntersection(e));
else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
p.add(l.getIntersection(a));
else if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
p.add(l.getIntersection(b));
return p;
}
else if(l.getIntersection(e)!=null&&l.getIntersection(d)!=null&&l.getIntersection(e).equals(l.getIntersection(d))) {
p.add(l.getIntersection(d));
if(l.getIntersection(b)!=null&&l.getIntersection(a)!=null&&l.getIntersection(b).equals(l.getIntersection(a)))
p.add(l.getIntersection(b));
else if(l.getIntersection(b)!=null&&l.getIntersection(c)!=null&&l.getIntersection(b).equals(l.getIntersection(c)))
p.add(l.getIntersection(c));
else if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
p.add(l.getIntersection(c));
else if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
p.add(l.getIntersection(a));
else if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
p.add(l.getIntersection(b));
return p;
}

if((l.getIntersection(a)!=null&&a.isBetween(l.getIntersection(a))))
p.add(l.getIntersection(a));
if((l.getIntersection(b)!=null&&b.isBetween(l.getIntersection(b))))
p.add(l.getIntersection(b));
if((l.getIntersection(c)!=null&&c.isBetween(l.getIntersection(c))))
p.add(l.getIntersection(c));
if((l.getIntersection(d)!=null&&d.isBetween(l.getIntersection(d))))
p.add(l.getIntersection(d));
if((l.getIntersection(e)!=null&&e.isBetween(l.getIntersection(e))))
p.add(l.getIntersection(e));

return p;

}

　　

三、踩坑心得

1、还是没有养成边码代码边写注释的习惯，再加上这次题目十分复杂，代码行数已经达到了2000行以上，方法数十分地多，这就导致我经常忘记哪个方法是干什么的，以后一定养成边码代码边写注释的习惯。

2、没有对重复出现的代码方法话，导致代码复用率特别高，尤其是在穷举时。

3、用了大量的判断语句导致代码的圈复杂度特别高

4、没有找到合适的数学方法，导致在判断某些东西时漏掉情况。

 

四、改进建议

   1. 在定义方法时，选取高效的算法降低代码运行时占用的内存，并降低运行时间，若算法差，则代码冗长，可读性差。 

 

   2. 尽可能减少代码复用，提高代码质量。

 

   3. 需要养成及时写注释的习惯，在这次写博客的过程中就深刻体会到了这一点，因为前两次作业都过了有一段时间，这就导致我完全不记得流程，这就浪费了我大量时间来回顾题目复习代码，实在是费时费力。并且希望以后在审完题后花一段时间来构思代码，合理分配职责，让代码的复杂度下降，并提高代码整体的美观性。

 

 　4.依据题目要求设计类，设计类的固有属性和方法，分配好各类间的职责，尽量做到职责单一化，并且规划好各类的关系。把需要重复出现的语句设计成一个方法，需要用时只需调用即可，降低代码的耦合度。

 

五、总结

这三次作业考试最大的收获是深刻地理解了继承和多态的应用，让我深深地体会到了其的便利性，这是面向过程所不能带来的。这次的经历也让我知道了自己在算法方面也存在不足，无法设计出优良的代码结构。最后，在面对程序出现的各种错误时去面对出现的各种错误，遇到问题冷静处理分析，多方面寻找原因去解决，从而慢慢提高自己的代码能力，这也是一个合格的程序员所必须具备的能力。