1 files changed, 122 insertions, 0 deletions
diff --git a/misc/examples/algorithms/shape.cpp b/misc/examples/algorithms/shape.cpp
new file mode 100644
index 00000000..ea1f53d2
--- /dev/null
+++ b/misc/examples/algorithms/shape.cpp
@@ -0,0 +1,122 @@
+// Demo of polymorphism in C++
+
+#include <iostream>
+#include <memory>
+#include <vector>
+
+// Shape definition
+// ============================================================
+
+struct Point {
+    float x, y;
+};
+
+std::ostream& operator<<(std::ostream& os, const Point& p) {
+    os << " (" << p.x << "," << p.y << ")";
+    return os;
+}
+
+struct Shape {
+    virtual ~Shape();
+    virtual void draw() const = 0;
+
+    uint32_t color;
+    uint16_t style;
+    uint8_t thickness;
+    uint8_t hardness;
+};
+
+Shape::~Shape()
+{
+    std::cout << "base destructed" << std::endl;
+}
+
+// Triangle implementation
+// ============================================================
+
+struct Triangle : public Shape
+{
+    Triangle(Point a, Point b, Point c);
+    void draw() const override;
+
+    private: Point p[3];
+};
+
+
+Triangle::Triangle(Point a, Point b, Point c)
+    : p{a, b, c} {}
+
+void Triangle::draw() const
+{
+    std::cout << "Triangle :" 
+              << p[0] << p[1] << p[2]
+              << std::endl;
+}
+
+
+// Polygon implementation
+// ============================================================
+
+
+struct Polygon : public Shape
+{
+    ~Polygon();
+    void draw() const override;
+    void addPoint(const Point& p);
+
+    private: std::vector<Point> points;
+};
+
+
+void Polygon::addPoint(const Point& p)
+{
+    points.push_back(p);
+}
+
+Polygon::~Polygon()
+{
+    std::cout << "poly destructed" << std::endl;
+}
+
+void Polygon::draw() const
+{
+    std::cout << "Polygon  :";
+    for (auto& p : points)
+        std::cout << p ;
+    std::cout << std::endl;
+}
+
+
+// Test
+// ============================================================
+
+void testShape(const Shape* shape)
+{
+    shape->draw();
+}
+
+#include <array>
+
+int main(void)
+{
+    std::vector<std::unique_ptr<Shape>> shapes;
+
+    auto tri1 = std::make_unique<Triangle>(Point{5, 7}, Point{12, 7}, Point{12, 20});
+    auto pol1 = std::make_unique<Polygon>();
+    auto pol2 = std::make_unique<Polygon>();
+
+    for (auto& p: std::array<Point, 4>
+            {{{50, 72}, {123, 73}, {127, 201}, {828, 333}}})
+        pol1->addPoint(p);
+
+    for (auto& p: std::array<Point, 5>
+            {{{5, 7}, {12, 7}, {12, 20}, {82, 33}, {17, 56}}})
+        pol2->addPoint(p);
+
+    shapes.push_back(std::move(tri1));
+    shapes.push_back(std::move(pol1));
+    shapes.push_back(std::move(pol2));
+
+    for (auto& shape: shapes)
+        testShape(shape.get());
+}