how to print the MAC address - c++

Question

i created a client server program that displays the MAC and ip addresses of the clients and i have a function that gets the MAC address of the computer but I'm having trouble printing the MAC address in a listbox. I created a print function that did work before but i changed the code for finding the mac address and now its not working (also i don't know if i'm calling printMACaddress in the right place). I have two list boxes - one displays the ip address the other displays the MAC address. When i click the ip address i want the MAC address of that computer to be displayed but right now its not displaying. nothing happens when i click the ip address
void CmfcServerDlg::OnLbnSelchangeListClientaddr()
{
bool GetMACFromIP(BYTE Address[MAX_ADAPTER_ADDRESS_LENGTH], const std::string &selected_ip_adr);
}
void CmfcServerDlg::PrintMACaddress(unsigned char MACData[])
{
CString
strText;
strText.Format("%02X-%02X-%02X-%02X-%02X-%02X\n",MACData[0], MACData[1], MACData[2], MACData[3], MACData[4], MACData[5]);
m_ClientIdList.AddString(strText);
}
bool CmfcServerDlg::GetMACFromIP(BYTE Address[MAX_ADAPTER_ADDRESS_LENGTH], const std::string &selected_ip_adr)
{
IP_ADAPTER_INFO AdapterInfo[16];
DWORD dwBufLen = sizeof(AdapterInfo);
DWORD dwStatus = GetAdaptersInfo(
AdapterInfo,
&dwBufLen);
assert(dwStatus == ERROR_SUCCESS);
PIP_ADAPTER_INFO pAdapterInfo = AdapterInfo;
bool found = false;
do {
const IP_ADDR_STRING *addr_str = &pAdapterInfo->IpAddressList;
while(addr_str != NULL)
{
if(selected_ip_adr == addr_str->IpAddress.String)
{
found = true;
break;
}
}
if(found)
{
memcpy(Address, pAdapterInfo->Address, MAX_ADAPTER_ADDRESS_LENGTH);
PrintMACaddress(pAdapterInfo->Address); //problem here
break;
}
else
{
PrintMACaddress(pAdapterInfo->Address);
pAdapterInfo = pAdapterInfo->Next;
}
}
while(pAdapterInfo);
return found;
}

Answer 1

You do realize that your stated goal in the comment ("i am trying to find the MAC address of any computer that connects to the server") is not possible? MAC addresses are lower-level than IP addresses, they identify the "media port", i.e. the place where the cable sits.
You cannot get the MAC address for a client on the other side of a switch even, much less across the Internet.