Vector2

java.lang.Object
- eecs2030.lab4.Vector2

```
public final class Vector2
extends Object
```
A class that represents two dimensional spatial vectors (a direction and a magnitude). Every vector has a real-valued x-component and a y-component. The class provides some basic mathematical operations such as vector addition and subtraction, and scalar multiplicaton.

Author:

EECS2030 Fall 2016

Constructor Summary

Constructors
Constructor and Description
`Vector2()` Creates the vector `(0.0, 0.0)` with name equal to the empty string.
`Vector2(double x, double y)` Creates the vector `(x, y)`.
`Vector2(Vector2 other)` Creates a vector with the same components as another vector.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Vector2`	`add(Vector2 other)` Add a vector to this vector changing the components of this vector.
`static Vector2`	`add(Vector2 a, Vector2 b)` Returns a new `Vector2D` equal to `a + b`.
`static Vector2`	`dirVector(double theta)` Returns the vector having magnitude one pointing in the direction `theta` degrees from the x axis.
`boolean`	`equals(Object obj)` Compares this vector with the given object.
`double`	`getX()` Returns the x component of the vector.
`double`	`getY()` Returns the y component of the vector.
`int`	`hashCode()` Returns a hash code for this vector.
`double`	`mag()` Returns the magnitude of this vector.
`Vector2`	`multiply(double s)` Multiply this vector by a scalar amount changing the components of this vector.
`static Vector2`	`multiply(double s, Vector2 a)` Returns a new `Vector2D` equal to `s * a`.
`void`	`set(double x, double y)` Sets the x and y component of the vector.
`void`	`setX(double x)` Sets the x component of the vector.
`void`	`setY(double y)` Sets the y component of the vector.
`boolean`	`similarTo(Vector2 other, double tol)` Determines if two vectors are almost equal (similar).
`Vector2`	`subtract(Vector2 other)` Subtract a vector from this vector changing the components of this vector.
`static Vector2`	`subtract(Vector2 a, Vector2 b)` Returns a new `Vector2D` equal to `a - b`.
`String`	`toString()` Returns a string representation of the vector.

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Vector2
```
public Vector2()
```
    Creates the vector (0.0, 0.0) with name equal to the empty string.
  - Vector2
```
public Vector2(double x,
               double y)
```
    Creates the vector (x, y).
    
    Parameters:
    
    x - the x-component of the vector
    
    y - the y-component of the vector
  - Vector2
```
public Vector2(Vector2 other)
```
    Creates a vector with the same components as another vector.
    
    Parameters:
    
    other - a vector to copy the components from
- Method Detail
  - getX
```
public double getX()
```
    Returns the x component of the vector.
    
    Returns:
    
    the x component of the vector.
  - setX
```
public void setX(double x)
```
    Sets the x component of the vector.
    
    Parameters:
    
    x - the new value of the x component.
  - getY
```
public double getY()
```
    Returns the y component of the vector.
    
    Returns:
    
    the y component of the vector.
  - setY
```
public void setY(double y)
```
    Sets the y component of the vector.
    
    Parameters:
    
    y - the new value of the y component.
  - set
```
public void set(double x,
                double y)
```
    Sets the x and y component of the vector.
    
    Parameters:
    
    x - the new value of the x component.
    
    y - the new value of the y component.
  - add
```
public Vector2 add(Vector2 other)
```
    Add a vector to this vector changing the components of this vector.
    Mathematically, if this vector is a and the other vector is b then invoking this method is equivalent to computing a + b and assigning the value back to a.
    
    Parameters:
    
    other - the vector to add to this vector.
    
    Returns:
    
    this Vector2D object
  - subtract
```
public Vector2 subtract(Vector2 other)
```
    Subtract a vector from this vector changing the components of this vector.
    Mathematically, if this vector is a and the other vector is b then invoking this method is equivalent to computing a - b and assigning the value back to a.
    
    Parameters:
    
    other - the vector to subtract this vector.
    
    Returns:
    
    this Vector2D object
  - multiply
```
public Vector2 multiply(double s)
```
    Multiply this vector by a scalar amount changing the components of this vector.
    Mathematically, if this vector is a and the scalor is s then invoking this method is equivalent to computing s * a and assigning the value back to a.
    
    Parameters:
    
    s - the scalar value to multiply the vector by
    
    Returns:
    
    this Vector2D object
  - mag
```
public double mag()
```
    Returns the magnitude of this vector.
    
    Returns:
    
    the magnitude of this vector.
  - add
```
public static Vector2 add(Vector2 a,
                          Vector2 b)
```
    Returns a new Vector2D equal to a + b.
    
    Parameters:
    
    a - a vector
    
    b - another vector
    
    Returns:
    
    a new Vector2D equal to a + b
  - subtract
```
public static Vector2 subtract(Vector2 a,
                               Vector2 b)
```
    Returns a new Vector2D equal to a - b.
    
    Parameters:
    
    a - a vector
    
    b - another vector
    
    Returns:
    
    a new Vector2D equal to a - b
  - multiply
```
public static Vector2 multiply(double s,
                               Vector2 a)
```
    Returns a new Vector2D equal to s * a.
    
    Parameters:
    
    s - a scalar
    
    a - a vector
    
    Returns:
    
    a new Vector2D equal to s * a
  - dirVector
```
public static Vector2 dirVector(double theta)
```
    Returns the vector having magnitude one pointing in the direction theta degrees from the x axis.
    The components of the vector are equal to (Math.cos(rad), Math.sin(rad)) where rad is theta expressed in radians.
    
    Parameters:
    
    theta - the direction that the vector is pointing in measured in degrees from the x axis
    
    Returns:
    
    the unit vector pointing in the given direction
  - hashCode
```
public int hashCode()
```
    Returns a hash code for this vector.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    a hash code for this vector
  - equals
```
public boolean equals(Object obj)
```
    Compares this vector with the given object. The result is true if and only if the argument is not null and is a Vector2D object having the same components as this object.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    obj - the object to compare this vector against
    
    Returns:
    
    true if the given object represents a Vector2D equivalent to this point, false otherwise
  - toString
```
public String toString()
```
    Returns a string representation of the vector. The string is the name of the vector, followed by the comma separated components of the vector inside parentheses.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of the vector
  - similarTo
```
public boolean similarTo(Vector2 other,
                         double tol)
```
    Determines if two vectors are almost equal (similar). Two vectors are similar if the magnitude of their vector difference is smaller than the specified tolerance.
    
    Parameters:
    
    other - the other vector to compare
    
    tol - the threshold length of the vector difference (this - other)
    
    Returns:
    
    true if the length of (this - other) is less than tol, and false otherwise

Class Vector2

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Vector2

Vector2

Vector2

Method Detail

getX

setX

getY

setY

set

add

subtract

multiply

mag

add

subtract

multiply

dirVector

hashCode

equals

toString

similarTo