Point2D (Algorithms 4/e)

Object
- edu.princeton.cs.algs4.Point2D

All Implemented Interfaces:

Comparable<Point2D>
```
public final class Point2D
extends Object
implements Comparable<Point2D>
```
The Point class is an immutable data type to encapsulate a two-dimensional point with real-value coordinates.
Note: in order to deal with the difference behavior of double and Double with respect to -0.0 and +0.0, the Point2D constructor converts any coordinates that are -0.0 to +0.0.
For additional documentation, see Section 1.2 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

Author:

Robert Sedgewick, Kevin Wayne

Field Summary

Fields
Modifier and Type	Field and Description
`static Comparator<Point2D>`	`R_ORDER` Compares two points by polar radius.
`static Comparator<Point2D>`	`X_ORDER` Compares two points by x-coordinate.
`static Comparator<Point2D>`	`Y_ORDER` Compares two points by y-coordinate.

Constructor Summary

Constructors
Constructor and Description

Point2D(double x, double y)
Initializes a new point (x, y).

Constructors
Constructor and Description
`Point2D(double x, double y)` Initializes a new point (x, y).

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static double`	`area2(Point2D a, Point2D b, Point2D c)` Returns twice the signed area of the triangle a-b-c.
`Comparator<Point2D>`	`atan2Order()` Compares two points by atan2() angle (between –π and π) with respect to this point.
`static int`	`ccw(Point2D a, Point2D b, Point2D c)` Returns true if a→b→c is a counterclockwise turn.
`int`	`compareTo(Point2D that)` Compares two points by y-coordinate, breaking ties by x-coordinate.
`double`	`distanceSquaredTo(Point2D that)` Returns the square of the Euclidean distance between this point and that point.
`double`	`distanceTo(Point2D that)` Returns the Euclidean distance between this point and that point.
`Comparator<Point2D>`	`distanceToOrder()` Compares two points by distance to this point.
`void`	`draw()` Plot this point using standard draw.
`void`	`drawTo(Point2D that)` Plot a line from this point to that point using standard draw.
`boolean`	`equals(Object other)` Compares this point to the specified point.
`int`	`hashCode()` Returns an integer hash code for this point.
`static void`	`main(String[] args)` Unit tests the point data type.
`Comparator<Point2D>`	`polarOrder()` Compares two points by polar angle (between 0 and 2π) with respect to this point.
`double`	`r()` Returns the polar radius of this point.
`double`	`theta()` Returns the angle of this point in polar coordinates.
`String`	`toString()` Return a string representation of this point.
`double`	`x()` Returns the x-coordinate.
`double`	`y()` Returns the y-coordinate.

Methods inherited from class Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - X_ORDER
```
public static final Comparator<Point2D> X_ORDER
```
    Compares two points by x-coordinate.
  - Y_ORDER
```
public static final Comparator<Point2D> Y_ORDER
```
    Compares two points by y-coordinate.
  - R_ORDER
```
public static final Comparator<Point2D> R_ORDER
```
    Compares two points by polar radius.
- Constructor Detail
  - Point2D
```
public Point2D(double x,
               double y)
```
    Initializes a new point (x, y).
    
    Parameters:
    
    x - the x-coordinate
    
    y - the y-coordinate
    
    Throws:
    
    IllegalArgumentException - if either x or y is Double.NaN, Double.POSITIVE_INFINITY or Double.NEGATIVE_INFINITY
- Method Detail
  - x
```
public double x()
```
    Returns the x-coordinate.
    
    Returns:
    
    the x-coordinate
  - y
```
public double y()
```
    Returns the y-coordinate.
    
    Returns:
    
    the y-coordinate
  - r
```
public double r()
```
    Returns the polar radius of this point.
    
    Returns:
    
    the polar radius of this point in polar coordiantes: sqrt(x*x + y*y)
  - theta
```
public double theta()
```
    Returns the angle of this point in polar coordinates.
    
    Returns:
    
    the angle (in radians) of this point in polar coordiantes (between –π and π)
  - ccw
```
public static int ccw(Point2D a,
                      Point2D b,
                      Point2D c)
```
    Returns true if a→b→c is a counterclockwise turn.
    
    Parameters:
    
    a - first point
    
    b - second point
    
    c - third point
    
    Returns:
    
    { -1, 0, +1 } if a→b→c is a { clockwise, collinear; counterclocwise } turn.
  - area2
```
public static double area2(Point2D a,
                           Point2D b,
                           Point2D c)
```
    Returns twice the signed area of the triangle a-b-c.
    
    Parameters:
    
    a - first point
    
    b - second point
    
    c - third point
    
    Returns:
    
    twice the signed area of the triangle a-b-c
  - distanceTo
```
public double distanceTo(Point2D that)
```
    Returns the Euclidean distance between this point and that point.
    
    Parameters:
    
    that - the other point
    
    Returns:
    
    the Euclidean distance between this point and that point
  - distanceSquaredTo
```
public double distanceSquaredTo(Point2D that)
```
    Returns the square of the Euclidean distance between this point and that point.
    
    Parameters:
    
    that - the other point
    
    Returns:
    
    the square of the Euclidean distance between this point and that point
  - compareTo
```
public int compareTo(Point2D that)
```
    Compares two points by y-coordinate, breaking ties by x-coordinate. Formally, the invoking point (x0, y0) is less than the argument point (x1, y1) if and only if either y0 < y1 or if y0 == y1 and x0 < x1.
    
    Specified by:
    
    compareTo in interface Comparable<Point2D>
    
    Parameters:
    
    that - the other point
    
    Returns:
    
    the value 0 if this string is equal to the argument string (precisely when equals() returns true); a negative integer if this point is less than the argument point; and a positive integer if this point is greater than the argument point
  - polarOrder
```
public Comparator<Point2D> polarOrder()
```
    Compares two points by polar angle (between 0 and 2π) with respect to this point.
    
    Returns:
    
    the comparator
  - atan2Order
```
public Comparator<Point2D> atan2Order()
```
    Compares two points by atan2() angle (between –π and π) with respect to this point.
    
    Returns:
    
    the comparator
  - distanceToOrder
```
public Comparator<Point2D> distanceToOrder()
```
    Compares two points by distance to this point.
    
    Returns:
    
    the comparator
  - equals
```
public boolean equals(Object other)
```
    Compares this point to the specified point.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    other - the other point
    
    Returns:
    
    true if this point equals other; false otherwise
  - toString
```
public String toString()
```
    Return a string representation of this point.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of this point in the format (x, y)
  - hashCode
```
public int hashCode()
```
    Returns an integer hash code for this point.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    an integer hash code for this point
  - draw
```
public void draw()
```
    Plot this point using standard draw.
  - drawTo
```
public void drawTo(Point2D that)
```
    Plot a line from this point to that point using standard draw.
    
    Parameters:
    
    that - the other point
  - main
```
public static void main(String[] args)
```
    Unit tests the point data type.
    
    Parameters:
    
    args - the command-line arguments

Class Point2D

Field Summary

Constructor Summary

Method Summary

Methods inherited from class Object

Field Detail

X_ORDER

Y_ORDER

R_ORDER

Constructor Detail

Point2D

Method Detail

x

y

r

theta

ccw

area2

distanceTo

distanceSquaredTo

compareTo

polarOrder

atan2Order

distanceToOrder

equals

toString

hashCode

draw

drawTo

main