#include <iostream>
#include <fstream>

using namespace std::literals;
using std::endl;

class A
{
public:
   A(int value) {std::cout << "constructor" << endl; mValue = value;}
   virtual ~A() {std::cout << "destructor" << endl;}
   int f() {return mValue;}

private:
   int mValue;
};

int main()
{
   A *obj = static_cast<A*>(malloc(sizeof(A)));
   new (obj) A(7);

   std::cout << obj << ": " << obj->f() << endl;
   free(obj);
   std::cout << obj << ": " << obj->f() << endl;

   return 0;
}