C++怎么实现一个简单的反射机制_C++运行时类型信息(RTTI)与技巧

#include <typeinfo><br>if (typeid(obj) == typeid(MyClass)) {<br>    std::cout << "obj is MyClass";<br>}

Base* ptr = new Derived();<br>Derived* d = dynamic_cast<Derived*>(ptr);<br>if (d) {<br>    // 转型成功<br>}

#include <map><br>#include <string><br>#include <memory><br><br>class Base {<br>public:<br>    virtual ~Base() = default;<br>    virtual void say() { std::cout << "Hello"; }<br>};<br><br>class DerivedA : public Base {<br>public:<br>    void say() override { std::cout << "I'm A"; }<br>};<br><br>class DerivedB : public Base {<br>public:<br>    void say() override { std::cout << "I'm B"; }<br>};<br><br>using CreateFunc = std::unique_ptr<Base>(*)();<br>std::map<std::string, CreateFunc> factory;<br><br>template<typename T><br>std::unique_ptr<Base> createInstance() {<br>    return std::make_unique<T>();<br>}<br><br>void registerClass(const std::string& name) {<br>    factory[name] = &createInstance<T>;<br>}<br><br>std::unique_ptr<Base> createObject(const std::string& className) {<br>    if (factory.find(className) != factory.end()) {<br>        return factory[className]();<br>    }<br>    return nullptr;<br>}

registerClass<DerivedA>("A");<br>registerClass<DerivedB>("B");<br><br>auto obj = createObject("A");<br>if (obj) obj->say(); // 输出 I'm A

auto obj = createObject("A");<br>if (obj && typeid(*obj) == typeid(DerivedA)) {<br>    std::cout << "Created correct type."; <br>}

std::cout << typeid(*obj).name();

struct Register {<br>    Register(const std::string& name) {<br>        registerClass<T>(name);<br>    }<br>};<br><br>// 在类外定义一个静态变量触发注册<br>static Register reg("DerivedA");

#define REGISTER_CLASS(Class, Name) \<br>    static Register<Class> reg##Class(Name);