Re: Getting access to std::map value (a struct)
If I use insert, as in:
m_AgentsList.insert( std::make_pair(deviceID, thisagent));
Then get error:
SocketServer.cpp(524) : error C2663: 'insert' : 3 overloads have no legal
conversion for 'this' pointer
This time using the CAgents as below:
class CAgents
{
public:
CAgents()
{
m_Socket = 0;
m_dwDeviceID = 0;
// m_strLogin = TEXT("");
}; // default constructor - init values to sensible defaults
CAgents(const Socket* pSocket, const DWORD DeviceID, const std::string&
strLogin)
{
m_Socket = pSocket;
m_dwDeviceID = DeviceID;
m_strLogin = strLogin;
}
CAgents(const CAgents& rhs)
:m_Socket(rhs.GetSocket()), m_dwDeviceID(rhs.GetDeviceID()),
m_strLogin(rhs.GetLogin())
{}; // assign rhs = eg
const Socket* m_Socket; // ptr to socket for client
DWORD m_dwDeviceID; // (DeviceID) extn
std::string m_strLogin; // logon
DWORD GetDeviceID() const
{
return m_dwDeviceID;
}
std::string GetLogin() const
{
return m_strLogin;
}
const Socket* GetSocket() const
{
return m_Socket;
}
CAgents& operator=(const CAgents& rhs)
{
m_Socket = rhs.GetSocket();
m_dwDeviceID = rhs.GetDeviceID();
m_strLogin = rhs.GetLogin();
return *this;
}
};
Angus
"Angus" <nospam@gmail.com> wrote in message
news:uT65NUa5GHA.1196@TK2MSFTNGP02.phx.gbl...
Thanks
And one last question. How do I assign a agents to m_AgentsList?
I tried m_AgentsList[4] = thisagent;
But got
error C2678:
binary '[' : no operator defined which takes a left-hand operand of type
'const class std::map<int,class CSocketServer
::CAgents,struct std::less<int>,class std::allocator<class
CSocketServer::CAgents> >' (or there is no acceptable conversion)
Angus
"Alex Blekhman" <xfkt@oohay.moc> wrote in message
news:u12rxnX5GHA.4832@TK2MSFTNGP06.phx.gbl...
"Angus" <nospam@gmail.com> wrote in message
news:uNuIaGV5GHA.1196@TK2MSFTNGP02.phx.gbl...
Hello
I am struggling here with a std::map like this:
struct agents
{
Socket* agentsocket; // ptr to socket for client
DWORD dwDeviceID; // (DeviceID)
char szLogon[100]; // logon
};
agents thisagent;
thisagent.agentsocket = 0;
thisagent.dwDeviceID = 6;
lstrcpy(thisagent.szLogon, "Angus");
agents thatagent;
thatagent.agentsocket = 0;
thatagent.dwDeviceID = 8;
lstrcpy(thatagent.szLogon, "Lisa");
// std::map<Key,Val>:
std::map<int, agents> m_AgentsList;
m_AgentsList[4] = thisagent;
m_AgentsList[8] = thatagent;
So if I want to get access to the agents in
m_AgentsList[4] I would do this:
agents myagent = m_AgentsList[4]; // compile error line
std::cout << myagent.szLogon << std::endl;
Easy enough. This compiles in my test program. But if I
compile in my main
program I get this:
SocketServer.cpp(410) :
error C2678:
binary '[' : no operator defined which takes a left-hand
operand of type
'const class std::map<int,struct CSocketServe
r::agents,struct std::less<int>,class
std::allocator<struct
CSocketServer::agents> >' (or there is no acceptable
conversion)
I have exactly the same code in SocketServer.cpp as my
test code in a really
small test cpp file.
You cannot call `std::map::operator[]' on constant instance
of map. It happens because `std::map::operator[]'
a) can change map instance
b) returns non-const reference to contained object.
If you need to search for value on constant map instance,
then use `std::map::find' method:
std::map<int, agents>::const_iterator it =
m_AgentsList.find(4);
if(it != m_AgentsList.end())
{
const agents& a = it->second;
std::cout << a.szLogon << std::endl;
}