Inserting different types of objects in the STL list (Lists)

[Question]:

My goal is to create a container for a different type of object. All required classes are derived from the same class first, and then pressed into the container. See the following code: Synobject is a base class, Synpin and Synpin are subclasses derived from the base class,class synObject {
public :
synObject();
string GetClass();
string className;
};
synObject::synObject()
{
className = "synObject";
}
string synObject::GetClass()
{
return className;
}
class synPin : public synObject {
string pin;
public :
synPin();
void　 SetPin(string Pin);
string GetPin();
private:
};
synPin::synPin()
{
className = "synPin";
}
void synPin::SetPin(string Pin)
{
pin = Pin;
}
string synPin::GetPin()
{
return pin;
}
class synCell : public synObject {
string cell;
public :
synCell();
void　 SetCell(string Cell);
string GetCell();
private:
};
synCell::synCell()
{
className = "synCell";
}
void synCell::SetCell(string Cell)
{
cell = Cell;
}
string synCell::GetCell()
{
return cell;
}