std::map POD instancing

map-pod-instancing.cpp

#include <stdio.h>
#include <map>

class Object;

typedef std::map<int, Object> ObjectMap;
typedef std::map<int, Object*> ObjectPtrMap;

class Object {
public:
	Object() {
		printf("%s\n", __PRETTY_FUNCTION__);
	};
	Object(const Object& obj) {
		printf("%s\n", __PRETTY_FUNCTION__);
	};
	Object(int a) {
		printf("%s\n", __PRETTY_FUNCTION__);
	};
	~Object() {
		printf("%s\n", __PRETTY_FUNCTION__);
	};
};

int main() {
	printf("POD:\n");
	{
		ObjectMap a;
		a[1]=Object(1);
		a[2];
		a.clear();
	}
	printf("\ndynamic:\n");
	{
		ObjectPtrMap b;
		b[1]=new Object(1);
		b[2];
		for (ObjectPtrMap::iterator i=b.begin(); i!=b.end(); ++i) {
			//printf("k: %d  o: %p\n", i->first, (void*)i->second);
			if (i->second) {
				delete i->second;
			}
		}
		b.clear();
	}
	return 0;
}

output

POD:
Object::Object()
Object::Object(const Object&)
Object::Object(const Object&)
Object::~Object()
Object::~Object()
Object::Object(int)
Object::~Object()
Object::Object()
Object::Object(const Object&)
Object::Object(const Object&)
Object::~Object()
Object::~Object()
Object::~Object()
Object::~Object()

dynamic:
Object::Object(int)
Object::~Object()