C++ Eintrag in der Registry ändern

#include <iostream>
#include <windows.h>
using namespace std;

int main () {
	   HKEY hkey;

	    DWORD dwNum = 0;
	    DWORD dwData = sizeof(DWORD);

	    RegOpenKeyEx(HKEY_CURRENT_USER,"Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings",0,KEY_QUERY_VALUE,&hkey);

	        RegQueryValueEx(hkey,"ProxyEnable",0,NULL,(BYTE*)&dwNum,&dwData);
	        RegCloseKey(hkey);
	if(dwNum==1)
	    {

	       dwNum=0;
	       RegCreateKeyEx(HKEY_CURRENT_USER,"Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings",0,0,REG_OPTION_NON_VOLATILE,KEY_ALL_ACCESS,NULL,&hkey,0);
	       RegSetValueEx(hkey,"ProxyEnable",0,REG_DWORD,(BYTE*)&dwNum,sizeof(DWORD));
	       RegCloseKey(hkey);
	    }else{
	
	    	dwNum=1;
	    	RegCreateKeyEx(HKEY_CURRENT_USER,"Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings",0,0,REG_OPTION_NON_VOLATILE,KEY_ALL_ACCESS,NULL,&hkey,0);
	    	RegSetValueEx(hkey,"ProxyEnable",0,REG_DWORD,(BYTE*)&dwNum,sizeof(DWORD));
	    	RegCloseKey(hkey);
	    }
	    cout << "Ausgabe: " << endl;
	    cout << dwNum<< endl;
	    return 0;
}