// ==========================================================================
// $Id: vector2d.cpp,v 1.1 2011/10/19 03:24:41 jlang Exp $
// CSI2372 example Code for lecture 4
// ==========================================================================
// (C)opyright:
//
//   Jochen Lang
//   SITE, University of Ottawa
//   800 King Edward Ave.
//   Ottawa, On., K1N 6N5
//   Canada. 
//   http://www.site.uottawa.ca
// 
// Creator: jlang (Jochen Lang)
// Email:   jlang@site.uottawa.ca
// ==========================================================================
// $Log: vector2d.cpp,v $
// Revision 1.1  2011/10/19 03:24:41  jlang
// Added code for lecture 7
//
// Revision 1.1  2011/10/16 02:51:42  jlang
// Added files for lecture 06
//
// ==========================================================================
#include <iostream>
#include <cmath>
#include "vector2d.h"

Vector2D::Vector2D(double _x, double _y) : Point2D(_x,_y) { 
  d_length = std::sqrt(dot(*this));
}

Vector2D::Vector2D(const Point2D& _pt) : Point2D(_pt) { 
  d_length = std::sqrt(dot(*this));
}


/**
 * Dot product between two vectors
 */
double Vector2D::dot( const Vector2D& _oVect ) const {
  return d_x * _oVect.d_x + d_y * _oVect.d_y;
}

/**
 * Add a vector to this vector and return result 
 */
Vector2D Vector2D::add( const Vector2D& _oVector ) const {
  return Vector2D(d_x + _oVector.d_x,
		  d_y + _oVector.d_y);
}

/**
 * Subtract a vector from this vector and return result
 */
Vector2D Vector2D::subtract( const Vector2D& _oVector ) const {
  return Vector2D(d_x - _oVector.d_x,
		  d_y - _oVector.d_y);
}

Vector2D Vector2D::scale( double _scaling ) const {
  return Vector2D(_scaling*d_x,
		  _scaling*d_y);
}

/**
 * Return the vector normalized
 */
Vector2D Vector2D::normalize() const {
  if (d_length>1e-39)
    return Vector2D(d_x/d_length,
		    d_y/d_length);
  else 
    return *this;
}


double Vector2D::getLength() const {
  return d_length;
}