#include <iostream>
#include <string>
#include <string.h>

void pbin(int n, int bits)
{ unsigned int mask = 1<<(bits-1);
  while (mask != 0)
  { if (n & mask)
      cout << "1";
    else
      cout << "0";
    mask >>= 1; } }

void investigate(char name[], void * address, int size)
{ cout << name << " at address " << (unsigned int)address << " = ";
  pbin((unsigned int)address, 32);
  cout << "\n";
  for (int i=0; i<size; i+=1)
  { cout << "    ";
    pbin(*(i+(unsigned char *)address), 8);
    cout << "\n"; } }

struct cat
{ int tag;
  int bday;
  char name[4]; };

struct dog
{ int tag;
  int price;
  int bday; };

struct generic
{ int tag; };

void print(void * p)
{ int tag = ((generic *)p)->tag;
  if (tag == 'C')
  { cat * cp = (cat *)p;
    cout << "bday=" << cp->bday << ", name='" << cp->name << "'\n"; }
  else if (tag == 'D')
  { dog * dp = (dog *)p;
    cout << "bday=" << dp->bday << ", price=" << dp->price << "\n"; } }

void main()
{ cat * c1 = new cat;
  c1->tag='C';
  c1->bday=20060815;
  strcpy(c1->name, "jim");
  dog * c2 = new dog;
  c2->tag='D';
  c2->price=199;
  c2->bday=20051107;
  void * pets[3];
  pets[0] = c1;
  pets[1] = c2;
  investigate("cat c1", c1, sizeof(dog));
  investigate("dog c2", c2, sizeof(cat));
  investigate("pets", pets, sizeof(pets));
  print(c1);
  print(c2);
  print(pets[0]);
  print(pets[1]); }