C++ の instance_of

instanceof.cpp

// 参考: http://simple-asta.blogspot.jp/2013/06/c-instanceof.html
#include <iostream>

class Object {
	public:
		template<typename T>
		inline bool instance_of()
		{
			return dynamic_cast<const T*>(this) != 0;
		}
		virtual ~Object(){}
};

class Derived_One : public Object {
};

class Derived_Two : public Object {
};

int main() {
	Object *obj[2];
	obj[0] = new Derived_One();
	obj[1] = new Derived_Two();

	for (int i = 0; i < 2; ++i)
	{
		std::cout << "obj[" << i << "] is ";
		if (obj[i]->instance_of<Derived_One>()) {
			std::cout << "Derived_One!";
		} else if (obj[i]->instance_of<Derived_Two>()) {
			std::cout << "Derived_Two!";
		} else {
			throw "Unrecognized Object";
		}
		std::cout << std::endl;
	}
	
	return 0;
}