Error in game with DirectX Toolkit

I need some little help. I have 2 error in my game can someone help please ?

GameState.h

#pragma once
#include "SpriteBatch.h"
#include "Intro.h"
#include "SwitchScreen.h"

class GameState
{
public:
    GameState();
    ~GameState();

    void Update();
    void Draw(DirectX::SpriteBatch* spriteBatch);

public:

    enum ScreenType{Direct, Menu, Game};

private:

    ScreenType _screenType;
    Intro* _screen;
    SwitchScreen* _switch;

};

Intro.h

#pragma once
#include "SpriteBatch.h"

class Intro
{
public:
    Intro();
    ~Intro();

    void Update();
    void Draw(DirectX::SpriteBatch* spriteBatch);

private:

    float _timer = 0.0f;
};

SwitchScreen.h

#pragma once
#include "Content.h"
#include "SpriteBatch.h"
#include "SimpleMath.h"
#include "GameState.h"

class SwitchScreen
{
public:
    SwitchScreen();
    ~SwitchScreen();

    bool GetUpdate();
    bool getSwitch();

    void Update(GameState gameState);
    void Draw(DirectX::SpriteBatch* spriteBatch);

private:

    bool _update;
    float _alpha;
    bool _switch;
};

Error 1 error C2143:

syntax error : missing ';' before '*' \visual studio 2013\projects\jelly\jelly\gamestate.h 23

Error 2 error C4430:

missing type specifier - int assumed. Note: C++ does not support default-int \visual studio 2013\projects\jelly\jelly\gamestate.h 23

Thank you