从C ++入门班进入循环依赖

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问题描述

我下面这本书 - 学习C ++。我在章介绍类中间，我被困在解决头文件包括作为例子中有两类。

I am following the book - C++ Primer for learning C++. I'm in middle of the chapter introducing classes, and I'm stuck in resolving the header files include of two classes taken as example there.

下面是两个类和头文件：

Here are the two classes, and the header files:

#ifndef SCREENCLS_H
#define SCREENCLS_H

#include <iostream>

#include "WindowManager.h"

using namespace std;

class ScreenCls {
    friend void WindowManager::clear(ScreenIndex);

public:
    typedef string::size_type pos;
    ScreenCls() { }
    ScreenCls(pos height, pos width, char c): height(height), width(width), contents(height * width, c) { }

    ScreenCls &set(char);
    ScreenCls &set(pos, pos, char);

    char get() const { return contents[cursor]; }  // Implicitly inline

private:
    pos cursor;
    pos height;
    pos width;
    string contents;
};

#endif // SCREENCLS_H

ScreenCls.cpp

#include "ScreenCls.h"

char ScreenCls::get(pos r, pos c) const {
    pos row = r * width;
    return contents[row + c];
}

ScreenCls &ScreenCls::set(char ch) {
    contents[cursor] = ch;
    return *this;
}

ScreenCls &ScreenCls::set(pos r, pos c, char ch) {
    contents[r * width + c] = ch;
    return *this;
}

WindowManager.h

#ifndef WINDOWMANAGER_H
#define WINDOWMANAGER_H

#include <iostream>
#include <vector>
#include "ScreenCls.h"

using namespace std;

class WindowManager {

public:
    // location ID for each screen on window
    using ScreenIndex = vector<ScreenCls>::size_type;
    // reset the Screen at the given position to all blanks
    void clear(ScreenIndex);

private:
    vector<ScreenCls> screens{ Screen(24, 80, ' ') };
};

#endif // WINDOWMANAGER_H

WindowManager.cpp

#include "WindowManager.h"
#include "ScreenCls.h"

void WindowManager::clear(ScreenIndex index) {
    ScreenCls &s = screens[i];
    s.contents = string(s.height * s.width, ' ');
}

这是我的项目结构：

/src/ScreenCls.cpp
/src/WindowManager.cpp
/include/ScreenCls.h
/include/WindowManager.h

我使用的 code :: Blocks的的IDE。我已经添加了 / src目录和 /包括在编译器文件夹中的搜索目录的设置。我还添加项目根目录到搜索目录。

I'm using Code::Blocks IDE. I've added /src and /include folder in the Search Directory in the compiler Settings. I've also added the project root directory to the search directory.

现在，当我试图构建项目，它显示了以下错误：

Now, when I'm trying to build the project, it shows following errors:

'ScreenCls' was not declared in this scope (WindowManager.h)
'ScreenIndex' has not been declared (WindowManager.h)
'ScreenIndex' has not been declared (ScreenCls.h)

和我不知道这里发生了什么。我通过一些资源在网上搜索，发现的。而且它没有帮助在这里。有人可能需要一些时间来看看，并提出一个解决方案？

And I've no idea what's happening here. I searched through some resources online, and found this link. And it's not helping here. Can someone take some time to look and suggest a solution?

windowmanager