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  1. #include <iostream>
  2. #include <functional>
  3.  
  4. struct Coordinate
  5. {
  6.     double x;
  7.     double y;
  8.     Coordinate(double x, double y) : x(x), y(y) {}
  9. };
  10.  
  11. Coordinate operator*(double d, Coordinate c)
  12. { return {c.x*d, c.y*d}; }
  13.  
  14. Coordinate operator*(Coordinate c, double d)
  15. { return d*c; }
  16.  
  17. Coordinate operator+(Coordinate lhs, Coordinate rhs)
  18. { return {lhs.x +rhs.x, lhs.y + rhs.y}; }
  19.  
  20. std::ostream& operator<<(std::ostream& out, const Coordinate& c)
  21. { return out << '(' << c.x << ", " << c.y << ')'; }
  22.  
  23. class Line
  24. {
  25. public:
  26.     Line(const Coordinate& start, const Coordinate& end)
  27.         : mP1(start), mP2(end)
  28.     {}
  29.  
  30.     std::function<Coordinate(double)> get_path() const
  31.     {
  32.         return [this](double t) {
  33.             return (1-t)*this->mP1 + t*this->mP2;
  34.         };
  35.     }
  36. private:
  37.     Coordinate mP1;
  38.     Coordinate mP2;
  39. };
  40.  
  41. struct Movable {
  42.     std::function<Coordinate(double)>  mpPath;
  43.  
  44.     template<typename T>
  45.     void setPath(const T& obj)
  46.     {
  47.         mpPath = obj.get_path();
  48.     }
  49.  
  50.     Coordinate position(double d)
  51.     {
  52.         return mpPath(d);
  53.     }
  54. };
  55.  
  56. int main()
  57. {
  58.     Line my_line(Coordinate(0.0, 0.0),
  59.                  Coordinate(10.0, 10.0));
  60.     Movable object2;
  61.     object2.setPath(my_line);
  62.     std::cout << object2.position(0.5); // prints (5, 5)
  63. }
Success #stdin #stdout 0s 3472KB
comments (?)
stdin 
Standard input is empty
stdout 
(5, 5)
https://ideone.com/3HKAsd
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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