以下是一个使用 C++ 实现的经典原型模式示例，包含测试代码：
#include <iostream>
#include <string>
#include <memory>// 抽象原型类
class Shape {
public:virtual ~Shape() = default;virtual std::unique_ptr<Shape> clone() const = 0;virtual void draw() const = 0;virtual void setColor(const std::string& color) = 0;
};// 具体原型类：圆形
class Circle : public Shape {std::string color;double radius;double x, y;public:Circle(const std::string& color, double radius): color(color), radius(radius), x(0), y(0) {}// 拷贝构造函数（用于克隆）Circle(const Circle& other) : color(other.color), radius(other.radius), x(other.x), y(other.y) {}std::unique_ptr<Shape> clone() const override {return std::make_unique<Circle>(*this);}void draw() const override {std::cout << "Drawing Circle at (" << x << ", " << y << ") with radius " << radius << " and color " << color << "\n";}void setPosition(double x, double y) {this->x = x;this->y = y;}void setColor(const std::string& color) override {this->color = color;}
};// 具体原型类：矩形
class Rectangle : public Shape {std::string color;double width;double height;double x, y;public:Rectangle(const std::string& color, double w, double h): color(color), width(w), height(h), x(0), y(0) {}Rectangle(const Rectangle& other): color(other.color), width(other.width), height(other.height),x(other.x), y(other.y) {}std::unique_ptr<Shape> clone() const override {return std::make_unique<Rectangle>(*this);}void draw() const override {std::cout << "Drawing Rectangle at (" << x << ", " << y << ") size " << width << "x" << height<< " color " << color << "\n";}void setPosition(double x, double y) {this->x = x;this->y = y;}void setColor(const std::string& color) override {this->color = color;}
};// 客户端/测试代码
int main() {// 创建原型对象Circle circlePrototype("Red", 10.0);Rectangle rectanglePrototype("Blue", 20.0, 30.0);// 克隆并修改圆形auto clonedCircle = circlePrototype.clone();clonedCircle->setColor("Green");dynamic_cast<Circle*>(clonedCircle.get())->setPosition(5, 5);// 克隆并修改矩形auto clonedRect = rectanglePrototype.clone();clonedRect->setColor("Yellow");dynamic_cast<Rectangle*>(clonedRect.get())->setPosition(10, 10);// 测试输出std::cout << "Original Circle:\n";circlePrototype.draw();std::cout << "\nCloned Circle:\n";clonedCircle->draw();std::cout << "\nOriginal Rectangle:\n";rectanglePrototype.draw();std::cout << "\nCloned Rectangle:\n";clonedRect->draw();// 验证深拷贝auto anotherClone = circlePrototype.clone();dynamic_cast<Circle*>(anotherClone.get())->setPosition(100, 100);std::cout << "\nModified clone position:\n";anotherClone->draw();std::cout << "Original circle position remains unchanged:\n";circlePrototype.draw();return 0;
}
这个示例演示了：
-
原型模式结构：
Shape是抽象原型接口Circle和Rectangle是具体原型类- 使用
clone()方法创建新对象
-
关键实现细节：
- 使用拷贝构造函数实现克隆
- 通过智能指针（unique_ptr）管理对象生命周期
- 支持深拷贝（所有成员变量都被正确复制）
- 提供修改方法验证克隆独立性
-
测试验证内容：
- 克隆对象的基本功能
- 修改克隆对象不影响原型
- 类型正确性（通过 dynamic_cast）
- 深拷贝的正确性验证
输出结果示例：
Original Circle:
Drawing Circle at (0, 0) with radius 10 and color RedCloned Circle:
Drawing Circle at (5, 5) with radius 10 and color GreenOriginal Rectangle:
Drawing Rectangle at (0, 0) size 20x30 color BlueCloned Rectangle:
Drawing Rectangle at (10, 10) size 20x30 color YellowModified clone position:
Drawing Circle at (100, 100) with radius 10 and color Red
Original circle position remains unchanged:
Drawing Circle at (0, 0) with radius 10 and color Red
这个示例展示了原型模式的核心思想：通过克隆现有对象来创建新对象，同时保持克隆对象与原型对象的独立性。使用智能指针可以自动管理内存，而通过拷贝构造函数实现的深拷贝确保了对象状态的独立复制。