shapes.hpp

Go to the documentation of this file.

 
#pragma once
 
#include <cmath>
#include <string>
#include <memory>
#include <vector>

 
namespace geometry {

class Shape {
public:
    virtual ~Shape() = default;

    [[nodiscard]] virtual double area() const = 0;

    [[nodiscard]] virtual double perimeter() const = 0;

    [[nodiscard]] virtual std::string name() const = 0;

    [[nodiscard]] std::string describe() const {
        return name() + "(area=" + std::to_string(area())
               + ", perimeter=" + std::to_string(perimeter()) + ")";
    }

    static int instance_count() { return instance_count_; }
 
protected:
    Shape() { ++instance_count_; }
 
private:
    static inline int instance_count_ = 0; 
};

class Circle : public Shape {
public:
    explicit Circle(double radius) : radius_(radius) {}
 
    [[nodiscard]] double area() const override {
        return M_PI * radius_ * radius_;
    }
 
    [[nodiscard]] double perimeter() const override {
        return 2.0 * M_PI * radius_;
    }
 
    [[nodiscard]] std::string name() const override { return "Circle"; }

    [[nodiscard]] double radius() const { return radius_; }
 
private:
    double radius_; 
};

class Rectangle : public Shape {
public:
    Rectangle(double width, double height) : width_(width), height_(height) {}
 
    [[nodiscard]] double area() const override {
        return width_ * height_;
    }
 
    [[nodiscard]] double perimeter() const override {
        return 2.0 * (width_ + height_);
    }
 
    [[nodiscard]] std::string name() const override { return "Rectangle"; }

    [[nodiscard]] double width() const { return width_; }
    [[nodiscard]] double height() const { return height_; }
 
protected:
    double width_;  
    double height_; 
};

class Square : public Rectangle {
public:
    explicit Square(double side) : Rectangle(side, side) {}
 
    [[nodiscard]] std::string name() const override { return "Square"; }

    [[nodiscard]] double side() const { return width_; }
};

class Triangle : public Shape {
public:
    Triangle(double a, double b, double c) : a_(a), b_(b), c_(c) {}
 
    [[nodiscard]] double area() const override {
        double s = (a_ + b_ + c_) / 2.0;
        return std::sqrt(s * (s - a_) * (s - b_) * (s - c_));
    }
 
    [[nodiscard]] double perimeter() const override {
        return a_ + b_ + c_;
    }
 
    [[nodiscard]] std::string name() const override { return "Triangle"; }
 
private:
    double a_; 
    double b_; 
    double c_; 
};

inline std::vector<std::unique_ptr<Shape>> make_demo_shapes() {
    std::vector<std::unique_ptr<Shape>> shapes;
    shapes.push_back(std::make_unique<Circle>(5.0));
    shapes.push_back(std::make_unique<Rectangle>(4.0, 6.0));
    shapes.push_back(std::make_unique<Square>(3.0));
    shapes.push_back(std::make_unique<Triangle>(3.0, 4.0, 5.0));
    return shapes;
}
 
} // namespace geometry
 // end of shapes group