How to gain Access to member variables of a class using void pointer but Not Object

Question

I am trying to access member variables of a class without using object. please let me know how to go about.

class TestMem
{
    int a;
    int b;
public:
    Tes         


        

Answer 1

I came up with a solution but it's dirty:

class TestMem
{
public:
    int a;
    int b;
    TestMem(){}
    void TestMem1()
    {
        a = 10;
        b = 20;
    }
};

void* offset(void* ptr, ...)
{
  va_list ap;
  va_start(ap, ptr); // get 1st argument's address

  long i = va_arg(ap, long); // get next argument
  va_end(ap);

  return (char*)ptr + i;
}

void test()
{
  TestMem t;
  void* p = (TestMem*)&t;
  t.a = 8;
  t.b = 9;
  printf("%i\n", *(int*)offset(p, &TestMem::a));
  printf("%i\n", *(int*)offset(p, &TestMem::b));
}