C++ : Declaring struct return-type function in header file

问题

I have a header file "check.h" that defines the following struct:

#ifndef CHECK_H
#define CHECK_H
#include<string>
struct Test{
    std::string check;

};

#endif  

I have another header file "test.h" that has the following function with return type as the struct Test defined above:

#ifndef TEST_H
#define TEST_H
#include<string>
#include "check.h"
Test display(std::string);
#endif  

But even on including "check.h" in this header file I get an unable to resolve identifier error. What do I do to fix this?

回答1:

Your code should be fine as long as you haven't defined something else (such as a variable or function) with the name Test.

If you have, then you need to make it clear that you're referring to the class and not the other thing:

struct Test display(std::string);
^^^^^^

although a much better solution would be to avoid using the same name for different things.

回答2:

You should return struct Test because test.h defines a struct not a type.

Or just change your struct definition to a typedef:

typedef struct s_Test{
    string check;
} Test;

See wikipedia there

来源：https://stackoverflow.com/questions/13838531/c-declaring-struct-return-type-function-in-header-file