// -*- c++ -*-

/**

2 dimensional vector (plainvector) implementation

*/

#ifndef HUGO_XY_H

#define HUGO_XY_H

#include <iostream>

namespace hugo {

  template<typename T>

    class xy {

    T _x,_y;

    public:

      ///Default constructor: both coordinates become 0

      xy() { _x=_y=0; }

      ///Constructing from coordinates

      xy(T a, T b) { _x=a; _y=b; }

      ///Gives back the x coordinate

      T x(){

	return _x;

      };

      ///Gives back the y coordinate

      T y(){

	return _y;

      };

      ///Gives back the square of the norm of the vector

      T normSquare(){

	return _x*_x+_y*_y;

      };

      ///Increments the left hand side by u

      xy<T>& operator +=(const xy<T>& u){

	_x += u._x;

	_y += u._y;

	return *this;

      };

      ///Decrements the left hand side by u

      xy<T>& operator -=(const xy<T>& u){

	_x -= u._x;

	_y -= u._y;

	return *this;

      };

      ///Multiplying the left hand side with a scalar

      xy<T>& operator *=(const T &u){

	_x *= u;

	_y *= u;

	return *this;

      };

      ///Dividing the left hand side by a scalar

      xy<T>& operator /=(const T &u){

	_x /= u;

	_y /= u;

	return *this;

      };

      ///Returns the scalar product of two vectors

      T operator *(const xy<T>& u){

	return _x*u._x+_y*u._y;

      };

      ///Returns the sum of two vectors

      xy<T> operator+(const xy<T> &u) const {

	xy<T> b=*this;

	return b+=u;

      };

      ///Returns the difference of two vectors

      xy<T> operator-(const xy<T> &u) const {

	xy<T> b=*this;

	return b-=u;

      };

      ///Returns a vector multiplied by a scalar

      xy<T> operator*(const T &u) const {

	xy<T> b=*this;

	return b*=u;

      };

      ///Returns a vector divided by a scalar

      xy<T> operator/(const T &u) const {

	xy<T> b=*this;

	return b/=u;

      };

      ///Testing equality

      bool operator==(const xy<T> &u){

	return (_x==u._x) && (_y==u._y);

      };

      ///Testing inequality

      bool operator!=(xy u){

	return  (_x!=u._x) || (_y!=u._y);

      };

    };

  ///Reading a plainvector from a stream

  template<typename T>

  inline

  std::istream& operator>>(std::istream &is, xy<T> &z)

  {

    ///This is not the best solution here: I didn't know how to solve this with friend functions

    T a,b;

    is >> a >> b;

    xy<T> buf(a,b);

    z=buf;

    return is;

  }

  ///Outputting a plainvector to a stream

  template<typename T>

  inline

  std::ostream& operator<<(std::ostream &os, xy<T> z)

  {

    os << "(" << z.x() << ", " << z.y() << ")";

    return os;

  }

} //namespace hugo

#endif //HUGO_XY_H