55 lines
1.0 KiB
C++
55 lines
1.0 KiB
C++
#include <iostream>
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#include <memory>
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struct Shape {
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virtual float area() const
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{
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std::cout << "Shape::area\n";
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return 0;
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}
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virtual ~Shape() {}
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};
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struct Rect : public Shape {
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Rect(float width, float height) : width(width), height(height) {}
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float area() const override
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{
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std::cout << "Rect::area\n";
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return width * height;
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}
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float width, height;
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};
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int main()
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{
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std::cout << "size of Shape: " << sizeof(Shape) << "\n"
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<< "size of Rect: " << sizeof(Rect) << "\n";
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Rect rect{2.0f, 3.0f};
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{
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const auto area = rect.area();
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std::cout << "Area of rect: " << area << "\n";
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}
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Shape shape = rect; // rect gets sliced to fit into shape.
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{
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const auto area = shape.area();
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std::cout << "Area of shape: " << area << "\n";
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}
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Shape *shape_ptr = ▭
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{
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const auto area = shape_ptr->area();
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std::cout << "Area of shape_ptr: " << area << "\n";
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}
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std::shared_ptr<Shape> shape_sptr = std::make_shared<Rect>(3.0f, 4.0f);
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{
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const auto area = shape_sptr->area();
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std::cout << "Area of shape_sptr: " << area << "\n";
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}
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}
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