An introduction to the C++ programming language for game engine development.

2. ‫ها‬ ‫کالس‬ ‫مراتب‬ ‫سلسله‬
‫کالس‬ ‫مراتب‬ ‫سلسله‬ ‫از‬ ‫استفاده‬ ‫فواید‬‫ها‬

3. 01. class Shape {
02. public:
03. virtual Point center() const = 0;// Pure virtual
04. virtual void move(Point to) = 0;
05. virtual void draw() const = 0;// Draw on current "Canvas"
06. virtual void rotate(int angle) = 0;
07.
08. virtual ~Shape() {}// Destructor
09. // ...
10. };

4. 01. // Rotate v's elements by angle degrees
02. void rotate_all(vector<Shape*>& v, int angle)
03. {
04. for (auto p : v)
05. p->rotate(angle);
06. }

5. 01. class Circle : public Shape {
02. public:
03. Circle(Point p, int rr); // Constructor
04. Point center() const { return x; }
05. void move(Point to) { x = to; }
06. void draw() const;
07. void rotate(int) {} // Nice simple algorithm
08. private:
09. Point x; // Center
10. int r; // Radius
11. };

6. 01. // Use the circle as the base for a face
02. class Smiley : public Circle {
03. public:
04. Smiley(Point p, int r) : Circle(p, r), mouth(nullptr) {}
05. ~Smiley() {
06. delete mouth;
07. for (auto p : eyes) delete p;
08. }
09. void move(Point to);
10. void draw() const;
11. void rotate(int);
12. void add_eye(Shape* s) { eyes.push_back(s); }
13. void set_mouth(Shape* s);
14. virtual void wink(int i); // Wink eye number i
15. // ...
16. private:
17. vector<Shape*> eyes; // Usually two eyes
18. Shape* mouth;
19. };

7. 01. void Smiley::draw()
02. {
03. Circle::draw();
04. for (auto p : eyes)
05. p->draw();
06. mouth->draw();
07. }

8. ‫رسیدن‬ ‫ارث‬ ‫به‬Interface‫ها‬
‫تر‬ ‫راحت‬ ‫سازی‬ ‫پیاده‬