Chapter 8, Problem 15E

Explanation of Solution

Program:

//definition of "Line" class

public class Line

{

    /*create the two objects for the "Point" class*/

    private Point p1;

    private Point p2;

    // definition of constructor

    public Line(Point p1, Point p2)

    {

        /*set the points to the "Point" class object*/

        this.p1 = p1;

        this.p2 = p2;

    }

    //definition of "getP1" method

    public Point getP1()

    {

        // returns this line's first endpoint

        return p1;

    }

    //definition of "getP2" method

    public Point getP2()

    {

        // returns this line's second endpoint

        return p2;

    }

    //definition of "toString" method

    public String toString()

    {

/*returns a string representation of this line*/

        return "[" + p1 + ", " + p2 + "]";

    }

    //definition of "getSlope" method

    public double getSlope()

    {

        //check two points are equal

        if (p1...