.cpp 文件在编译时看不到.h 文件

Question

I am trying to compile a unit for a class, which I have split into a .hpp and .cpp file. The files are called player.hpp and player.cpp .

I used the command g++ -c player.cpp .

Here is player.hpp

#define PLAYER
#ifndef PLAYER

#include <string>
#include <iostream>

class Player
{
    private:
        char symbol;
        std::string name;
    public:
        Player(char symbol, std::string name);
        std::string makeMove(); // Prompts the player to input a move to make
}

#endif            

and here is player.cpp

#include "player.hpp"

Player::Player(char symbol)
{
    this->symbol = symbol;
    this->name = name;
}

std::string Player::makeMove()
{
    std::string playerMove;
    std::cout << this->name << "'s turn.\nPlease make your move (enter as number combination of row and column. ex: 13 = First row, third column)\n";
    std::cin << playerMove;
    return playerMove;
}         

Here is the output

player.cpp:3:1: error: ‘Player’ does not name a type
    3 | Player::Player(char symbol)
      | ^~~~~~
player.cpp:9:6: error: ‘string’ in namespace ‘std’ does not name a type
    9 | std::string Player::makeMove()
      |      ^~~~~~
player.cpp:2:1: note: ‘std::string’ is defined in header ‘<string>’; did you forget to ‘#include <string>’?
    1 | #include "player.hpp"
  +++ |+#include <string>
    2 | 

It would seem that my .hpp file is not being included properly, why?

Answer 1

In your player.hpp , the order of lines in the include guard is incorrect. It should be:

#ifndef PLAYER
#define PLAYER