消息:: Simbolo使用未定义的类符号

错误c2079'消息:: simbolo'使用未定义的类'符号'

编译时在此行上生成

    Symbol simbolo;

这是我的C 代码：

类消息

#pragma once
#include <string>
#include "Symbol.h"
#include "SharedEditor.h"
class SharedEditor;
class Symbol;

class Message
{
private:
    SharedEditor* sender;
    int action; //1 inserted 2 deleted
    Symbol simbolo;
public:
    Message();
    Message(SharedEditor* sender, Symbol nuovosimbolo, int action);
    ~Message();
};

类符号

#pragma once
#include "SharedEditor.h"
#include <vector>
class SharedEditor;
class Message;
class Symbol
{
    char character;
    int siteID;
    SharedEditor* generator;
    std::vector<int> position;
public:
    Symbol();
    Symbol(char ch, SharedEditor* source, int ID, std::vector<int> pos);
    ~Symbol();
};

类共享词：

#pragma once
#include "NetworkServer.h"
#include "Message.h"
#include "Symbol.h"

class Message;
class Symbol;

class SharedEditor
{
private:
    NetworkServer& _server;
    int _siteId;
    std::vector<Symbol> _symbols;
   //other functions
public:
    SharedEditor(NetworkServer ns);
    ~SharedEditor();
    void process(const Message& m);
};

类NetworkServer：

#pragma once
#include <iostream>
#include <vector>
#include <queue>
#include "SharedEditor.h"
#include "Message.h"
class SharedEditor;
class Message;

class NetworkServer
{
private:
    std::vector<SharedEditor*> connected;
    std::queue<Message> codaMessaggi;
public:
    int connect(SharedEditor* sharedEditor);
    void disconnect(SharedEditor* sharedEditor);
    void send(const Message& m);
    NetworkServer();
    ~NetworkServer();
};