Mine

== socketaddress.h ==

class SocketAddress
{
public:
    virtual bool isValid() = 0;
    virtual operator struct sockaddr *() = 0;
    virtual operator socklen_t() = 0;
    virtual ~SocketAddress() {}
    SocketAddress() {}
};

== ipv4address.h ==

class IPv4Address : public SocketAddress
{
        public:
            IPv4Address(char* addr, char* port);
            IPv4Address(uint32_t addr, uint16_t port);
            IPv4Address(char* port);
            IPv4Address(uint16_t port);
            IPv4Address();
            ~IPv4Address();
            operator struct sockaddr * ();
            operator socklen_t();
            bool isValid();
        private:
            struct sockaddr_in m_addr;
};