public class Vector3D

{

  float x;

  float y;

  float z;



  public Vector3D( float X, float Y, float Z ) { 
    x = X; 
    y = Y; 
    z = Z;
  }

  public Vector3D() { 
    x = 0; 
    y = 0; 
    z = 0;
  }

  public Vector3D( Vector3D p ) { 
    x = p.x; 
    y = p.y; 
    z = p.z;
  }



  public final float z() { 
    return z;
  }

  public final float y() { 
    return y;
  }

  public final float x() { 
    return x;
  }



  public final void setX( float X ) { 
    x = X;
  }

  public final void setY( float Y ) { 
    y = Y;
  }

  public final void setZ( float Z ) { 
    z = Z;
  }



  public final void set( float X, float Y, float Z ) { 
    x = X; 
    y = Y; 
    z = Z;
  }



  public final void set( Vector3D p ) { 
    x = p.x; 
    y = p.y; 
    z = p.z;
  }



  public final void add( Vector3D p ) { 
    x += p.x; 
    y += p.y; 
    z += p.z;
  }

  public final void subtract( Vector3D p ) { 
    x -= p.x; 
    y -= p.y; 
    z -= p.z;
  }



  public final void add( float a, float b, float c ) { 
    x += a; 
    y += b; 
    z += c;
  } 

  public final void subtract( float a, float b, float c ) { 
    x -= a; 
    y -= b; 
    z -= c;
  } 



  public final Vector3D multiplyBy( float f ) { 
    x *= f; 
    y *= f; 
    z*= f; 
    return this;
  }



  public final float distanceTo( Vector3D p ) { 
    return (float)Math.sqrt( distanceSquaredTo( p ) );
  }



  public final float distanceSquaredTo( Vector3D p ) { 
    float dx = x-p.x; 
    float dy = y-p.y; 
    float dz = z-p.z; 
    return dx*dx + dy*dy + dz*dz;
  }



  public final float distanceTo( float x, float y, float z )

  {

    float dx = this.x - x;

    float dy = this.y - y;

    float dz = this.z - z;

    return (float)Math.sqrt( dx*dx + dy*dy + dz*dz );
  }



  public final float dot( Vector3D p ) { 
    return x*p.x + y*p.y + z*p.z;
  }

  public final float length() { 
    return (float)Math.sqrt( x*x + y*y + z*z );
  }

  public final float lengthSquared() { 
    return x*x + y*y + z*z;
  }



  public final void clear() { 
    x = 0; 
    y = 0; 
    z = 0;
  }



  public final String toString() { 
    return new String( "(" + x + ", " + y + ", " + z + ")" );
  }



  public final Vector3D cross( Vector3D p )
  {
    return new Vector3D( 	this.y*p.z - this.z*p.y, 
    this.x*p.z - this.z*p.x,
    this.x*p.y - this.y*p.x );
  }



  public boolean isZero() 
  {
    return x == 0 && y == 0 && z == 0;
  }
  
}