c++ - 错误 : ‘Page’ was not declared in this scope

Question

我有以下 C++ 类:

页面.h:

#ifndef PAGE_H_
#define PAGE_H_

#include "Process.h"

class Page {
public:
    Page();
    virtual ~Page();
    Process *process;
};

#endif /* PAGE_H_ */

和Process.h:

#ifndef PROCESS_H_
#define PROCESS_H_

#include <vector>
#include "Page.h"

class Process {
public:
    Process();
    virtual ~Process();

    int size;
    double life_remaining;
    std::vector<Page> pages;
};

#endif /* PROCESS_H_ */

编译时出现以下错误:

../src/Process.h:21:14: error: ‘Page’ was not declared in this scope
../src/Process.h:21:18: error: template argument 1 is invalid
../src/Process.h:21:18: error: template argument 2 is invalid

我该如何纠正这个问题？当我注释掉以下行时:#include "Proccess.h"和 Process *process;然后编译。当我删除评论时，它给我错误

Answer 1

在 Page.h 中使用前向声明而不是包含:

//replace this:
//#include "Process.h"

//with this:
class Process;

class Page {
public:
    Page();
    virtual ~Page();
    Process *process;
};