to pass in a unknown data and retrieving it

[themadme]

i want to set a class back to its original structure after calling a receive function. code below to explain

class Node
{
    public:
    Node(){}
    ~Node(){}
};
 
 
class lol  : public Node
{
    public:
    string strName;
};
 
class face
{
    public:
 
    void vSetLOL( CONST Node &C_lol )
    {
        this->C_lol  = C_lol;
    }
 
    const Node getLoL( void ) const
    {
        return C_lol;
    }
 
    priavte:
 
    Node C_lol ;    
}
 
 
main
{
    lol  C_lol;
    face C_face;
 
    C_lol.strname = "gums";
 
    C_face.vSetLOL( C_lol );
 
    C_lol.strname = " monkey";
 
 
    ////// how do you change the node C_lol back to lol C_lol /////
    C_lol = C_face.getLOL();  /// this is the main problem
 
}

[Ganon11]

You may be able to cast C_face.getLOL() to a C_lol, or have the face class hold a lol object instead of a Node object.

[Banfa]

The bottom line is that you can't. As soon as you copied a class lol to a class Node the value of any data members held in the lol were lost forever.

You may be able to write a constructor and operator= for lol that will take a Node & as the parameter but you will never be able to reconstruct any data held in lol.

[themadme]

Thanks for the replies and sorry about the bad naming in the last example

would that be the same problem if put a structure into a buffer.

//// class called Data
Data::Data()
{
    char *pcPacket = new char;
}
 
void Data::setPacketData( const char* pcPacketData )
{
    *pcPacket = *pcPacketData;
}
 
void Data::getPacketData( const char* pcPacketData )
{
    *pcPacketData = *pcPacket;
}
 
int main
{
     stucture vector3
     {
          int x,y, z;
     };
 
     Data C_Data;
     vector3 vec3;
 
      /// this would work
     C_Data.setPacketData( (char*)&vec3 );    
 
      /// this would not work, the returned data would not change?
      C_Data.getPacketData( (char*)&vec3 );    
 
     return 0;
}

so the returned data would be impossible to change or is there a mystic way? if was integers or floats that was put into the buffer, i know that would work but not with structures

when i allocate the pcPacket, i should put it into an array, depending on the size of the structure that was sent right?

[themadme]

oops found the problem, such amateur mistake, im only coping over one byte of data. someone slap me

[arnaudk]

*SLAP*!
Oops, message too short... *SLAP* *SLAP* *SLAP* ;-)

[themadme]

lol ok, new prob, will actually it not a problem yet.

I would just some comments back to see what i'm doing is correct.

//////////// this would be done on both sides of the server and the client
#define BUFFERSIZE 80
 
struct PacketData
{
    float x,y,z;
 
}S_PacketData;
 
struct Data
{
    char *pcPacket;
    char *cpName;
}S_Data;
 
S_Data.pcPacket = new char[ sizeof(PacketData) ];
S_Data.cpName = NULL;
 
char *NetPacket = new char[ sizeof(PacketData) + BUFFERSIZE ];
 
//////////////////////////////////////////////////////////////////////////////////////
 
//////// then on the client side it would do this to send information ////////////////
 
S_PacketData.x = 5.0f;
S_PacketData.y = 15.0f;
S_PacketData.z = 25.0f;
 
S_Data.cpName = "lols";
 
memcpy( S_Data.pcPacket, &S_PacketData, sizeof(PacketData) );
 
memcpy( NetPacket, &S_Data, sizeof(PacketData) + BUFFERSIZE );
 
send(s, NetPacket, sizeof(PacketData) + BUFFERSIZE,0);
 
 
///////////// on the server would have this ///////////////////
 
recv (s, NetPacket, sizeof(PacketData) + BUFFERSIZE,0);
 
/////// is this correct so far? /////////////////////////////////