MeyersCounting

#ifndef MEYERSCOUNTING_H_
#define MEYERSCOUNTING_H_

template<typename CountedType>
class ObjectCounter {
private:
	static size_t count;

protected:
	ObjectCounter() {
		++ObjectCounter<CountedType>::count;
	}

	ObjectCounter( const ObjectCounter<CountedType> &) {
		++ObjectCounter<CountedType>::count;
	}

	~ObjectCounter() {
		--ObjectCounter<CountedType>::count;
	}

public:
	static size_t liveCount() {
		return ObjectCounter<CountedType>::count;
	}
};

template<typename CountedType>
size_t ObjectCounter<CountedType>::count = 0;

class MyClass : public ObjectCounter<MyClass> {};

#endif

如果你想给自己的MyClass类计数，记录创建了多少个MyClass实例，那仅仅只需要继承就可以了。