///////////////////////////////////////////////////////////////
//  enumerate.cpp  -  traversing registry and displaying     //
//  ver 1.0           keys and values                        //
//                                                           //
//  Jim Fawcett, CST 2-187, Syracuse Univ                    //
//  fawcett@ecs.syr.edu, (315) 443-3948                      //
//                                                           //
//  Modified from Win32 System Services, Marshall Brain,     //
//  Prentice Hall, 1996                                      //
///////////////////////////////////////////////////////////////
//  Note:                                                    //
//    View result with regedit.exe (don't modify anything!)  //
//                                                           //
///////////////////////////////////////////////////////////////

#include <windows.h>
#include <iostream.h>

void main() {

  LONG ret;
  HKEY keyHandle;
  CHAR subKeyName[80];
  DWORD subKeyNameSize;
  CHAR valueName[80];
  DWORD valueNameSize;
  BYTE value[80];
  DWORD valueSize;
  DWORD n;
  FILETIME lastUpdate;

  cout << "\n  Demonstrating Traversal of the Registry Tree "
       << "\n ==============================================\n";

// open key to enumerate

  ret=RegOpenKeyEx(
        HKEY_CURRENT_USER,
        "Control Panel", 
        0,
        KEY_ENUMERATE_SUB_KEYS,
        &keyHandle
      );

  if (ret != ERROR_SUCCESS) {
    cerr << "\n  Unable to open subkey\n\n";
    return;
  }

//

  cout << "\nsubkeys of \"Control Panel\":\n";

// show all subkeys

  n=0;
  do
  {
    subKeyNameSize=80;
    ret=RegEnumKeyEx(
          keyHandle, 
          n,
          subKeyName, 
          &subKeyNameSize,
          NULL, 
          NULL, 
          NULL, 
          &lastUpdate
        );

    if (ret == ERROR_SUCCESS) {
      cout << "\n  " << subKeyName;
      n++;
    }
  } while (ret == ERROR_SUCCESS);

  cout << "\n\nThere are " << n << " keys listed." << endl;

// close key

  ret=RegCloseKey(keyHandle);
  
  if (ret != ERROR_SUCCESS) {
    cerr << "\n  Unable to close subkey\n\n";
    return;
  }

//

// open a specific subkey to enumerate

  ret=RegOpenKeyEx(
        HKEY_CURRENT_USER,
        "Control Panel\\Desktop",
        0, 
        KEY_QUERY_VALUE,
        &keyHandle
      );

  if (ret != ERROR_SUCCESS) {
    cerr << "\n  Unable to open subkey\n\n";
    return;
  }

  cout << "\nvalues of subkeys under \"Control Panel\\Desktop\":\n";

// show all values

  n=0;
  do
  {
    valueNameSize=80;
    valueSize=80;
    ret=RegEnumValue(
          keyHandle, 
          n,
          valueName, 
          &valueNameSize,
          NULL, 
          NULL, 
          value, 
          &valueSize
        );

    if (ret == ERROR_SUCCESS) {
      cout << "\n  " << valueName << " is " << value;
      n++;
    }
  } while (ret == ERROR_SUCCESS);

  cout << "\n\nThere are " << n << " key-value pairs listed.\n\n";

// close key

  ret=RegCloseKey(keyHandle);

  if (ret != ERROR_SUCCESS) {
    cerr << "Unable to close subkey\n\n";
    return;
  }
}