How do I determine which subclass an object is?

Hm, quick follow-up, am I doing this correctly? This version seems more straightforward but it doesn’t compile, it claims “None of the overloads could convert all argument types”:

FTestChild1 TC1;
	FTestChild1* testChildStruct = Cast<FTestChild1*>(TC1);
	if (testH) {
		GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, TEXT("Merry christmas!"));
	}