带你深入浅出设计模式：四、原型模式：编程中的克隆技术
此为设计模式第四谈！
用总-分-总的结构和生活化的例子给你讲解设计模式！
码农不易，各位学者学到东西请点赞收藏支持支持！
开始部分：
总：原型模式的核心逻辑在于通过克隆现有实例来创建新对象，而不是通过传统的构造函数，根据需求来修改属性。
分：
1.老规矩，打开VS创建一个控制台应用
2.实现编码，这里用制作三明治为讲解例子
2.1 创建抽象原型基类
2.2 实现原型类的克隆逻辑
2.3 创建原型实例
2.4 克隆对象
2.5 使用克隆对象
#include <iostream>
#include <map>
#include <string>
#include <vector>//1.创建抽象基类
class Sandwich {
public:Sandwich(std::string bread, std::string sauce, std::vector<std::string> toppings): _bread(bread), _sauce(sauce), _toppings(toppings) {}virtual Sandwich* clone() const = 0;//clone纯虚函数，用于克隆对象virtual void display() const = 0;//用于展示三明治属性protected:std::string _bread;//面包类型std::string _sauce;//酱汁类型std::vector<std::string> _toppings;//配料
};//经典火腿三明治类
class HamSandwich : public Sandwich {
public:HamSandwich(std::string bread, std::string sauce, std::vector<std::string> toppings): Sandwich(bread, sauce, toppings) {}//子类调用基类构造函数Sandwich* clone() const override {//重写clone方法，常量成员函数，不会修改调用该函数的对象的任何成员变量return new HamSandwich(*this);}void display() const override {std::cout << "Ham Sandwich - Bread: " << _bread<< ", Sauce: " << _sauce<< ", Toppings: ";for (const auto& topping : _toppings) {std::cout << topping << ' ';}std::cout << std::endl;}
};//意式蔬菜三明治类
class VeggieSandwich : public Sandwich {
public:VeggieSandwich(std::string bread, std::string sauce, std::vector<std::string> toppings): Sandwich(bread, sauce, toppings) {}Sandwich* clone() const override {return new VeggieSandwich(*this);}void display() const override {std::cout << "Veggie Sandwich - Bread: " << _bread<< ", Sauce: " << _sauce<< ", Toppings: ";for (const auto& topping : _toppings) {std::cout << topping << ' ';}std::cout << std::endl;}
};int main() {// 建立“原型”三明治Sandwich* hamPrototype = new HamSandwich("White", "Mayo",{"Ham", "Lettuce", "Tomato"});Sandwich* veggiePrototype = new VeggieSandwich("Wheat", "Pesto",{"Cucumber", "Avocado"});// 复制并个性化Sandwich* customerOrder1 = hamPrototype->clone(); // 点单经典火腿三明治customerOrder1->_sauce = "Mustard"; // 添加个人偏好customerOrder1->_toppings.push_back("Cheese");Sandwich* customerOrder2 = veggiePrototype->clone(); // 点单经典意式蔬菜三明治customerOrder2->_bread = "Sourdough"; // 更改面包customerOrder2->_toppings.push_back("Olives");// 展示订单customerOrder1->display();customerOrder2->display();// 清理delete hamPrototype;delete veggiePrototype;delete customerOrder1;delete customerOrder2;return 0;
}