This is the code of PointCP : public class PointCP { //Instance variables ************************************************ /**
Question:
This is the code of PointCP :
public class PointCP
{
//Instance variables ************************************************
/**
* Contains C(artesian) or P(olar) to identify the type of
* coordinates that are being dealt with.
*/
private char typeCoord;
/**
* Contains the current value of X or RHO depending on the type
* of coordinates.
*/
private double xOrRho;
/**
* Contains the current value of Y or THETA value depending on the
* type of coordinates.
*/
private double yOrTheta;
//Constructors ******************************************************
/**
* Constructs a coordinate object, with a type identifier.
*/
public PointCP(char type, double xOrRho, double yOrTheta)
{
if(type != 'C' && type != 'P')
throw new IllegalArgumentException();
this.xOrRho = xOrRho;
this.yOrTheta = yOrTheta;
typeCoord = type;
}
//Instance methods **************************************************
public double getX()
{
if(typeCoord == 'C')
return xOrRho;
else
return (Math.cos(Math.toRadians(yOrTheta)) * xOrRho);
}
public double getY()
{
if(typeCoord == 'C')
return yOrTheta;
else
return (Math.sin(Math.toRadians(yOrTheta)) * xOrRho);
}
public double getRho()
{
if(typeCoord == 'P')
return xOrRho;
else
return (Math.sqrt(Math.pow(xOrRho, 2) + Math.pow(yOrTheta, 2)));
}
public double getTheta()
{
if(typeCoord == 'P')
return yOrTheta;
else
return Math.toDegrees(Math.atan2(yOrTheta, xOrRho));
}
/**
* Converts Cartesian coordinates to Polar coordinates.
*/
public void convertStorageToPolar()
{
if(typeCoord != 'P')
{
//Calculate RHO and THETA
double temp = getRho();
yOrTheta = getTheta();
xOrRho = temp;
typeCoord = 'P'; //Change coord type identifier
}
}
/**
* Converts Polar coordinates to Cartesian coordinates.
*/
public void convertStorageToCartesian()
{
if(typeCoord != 'C')
{
//Calculate X and Y
double temp = getX();
yOrTheta = getY();
xOrRho = temp;
typeCoord = 'C'; //Change coord type identifier
}
}
/**
* Calculates the distance in between two points using the Pythagorean
* theorem (C ^ 2 = A ^ 2 + B ^ 2). Not needed until E2.30.
*
* @param pointA The first point.
* @param pointB The second point.
* @return The distance between the two points.
*/
public double getDistance(PointCP pointB)
{
// Obtain differences in X and Y, sign is not important as these values
// will be squared later.
double deltaX = getX() - pointB.getX();
double deltaY = getY() - pointB.getY();
return Math.sqrt((Math.pow(deltaX, 2) + Math.pow(deltaY, 2)));
}
/**
* Rotates the specified point by the specified number of degrees.
* Not required until E2.30
*
* @param point The point to rotate
* @param rotation The number of degrees to rotate the point.
* @return The rotated image of the original point.
*/
public PointCP rotatePoint(double rotation)
{
double radRotation = Math.toRadians(rotation);
double X = getX();
double Y = getY();
return new PointCP('C',
(Math.cos(radRotation) * X) - (Math.sin(radRotation) * Y),
(Math.sin(radRotation) * X) + (Math.cos(radRotation) * Y));
}
/**
* Returns information about the coordinates.
*
* @return A String containing information about the coordinates.
*/
public String toString()
{
return "Stored as " + (typeCoord == 'C'
? "Cartesian (" + getX() + "," + getY() + ")"
: "Polar [" + getRho() + "," + getTheta() + "]") + "\n";
}
}
Java How To Program Early Objects
ISBN: 9780134743356
11th Edition
Authors: Paul Deitel, Harvey Deitel