c++ - C++ 头文件为架构 x86_64 错误生成未定义符号

Question

当我将它们放在文件中时，这些函数都可以正常工作main.cpp，但是我现在已经将它们移到了头文件中。

这是我的general_functions.cpp：

#include <iostream>
#include <fstream>
#include <string>
#include <stdlib.h>
#include "general_functions.hpp"
using namespace std;


bool check_if_room_exists(int room_number){
    string room_number_full = to_string(room_number) + ".txt";
    ifstream new_file;
    new_file.open(room_number_full);

    if(new_file.is_open()){
        return true;
    }else{
        return false;
    }
    }

int get_new_room_number(){
    int room_number;
    cout<<"What room number do you want this room to have?"<<endl;
    cout<<"Enter your choice: ";
    cin>>room_number;

    while(!room_number || check_if_room_exists(room_number) == true){
        // Taken from StackOverflow to avoid endless loop: https://stackoverflow.com/questions/19521320/why-do-i-get-an-infinite-loop-if-i-enter-a-letter-rather-than-a-number
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
        // End of code taken from StackOverflow
        if(check_if_room_exists(room_number) == true){
            cout<<"A room with that number already exists.\nEnter your new choice: ";
        }else{
            cout<<"Please ensure you enter only numeric values for the room number.\nEnter your new choice: ";
        }
        cin>>room_number;
    }
    return room_number;
};

int get_cost_per_night(){
    int cost;
    cout<<"Please enter the cost per night for this room: ";
    cin >> cost;

    while(!cost || cost < 1){
        // Taken from StackOverflow to avoid endless loop: https://stackoverflow.com/questions/19521320/why-do-i-get-an-infinite-loop-if-i-enter-a-letter-rather-than-a-number
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
        // End of code taken from StackOverflow
        if(!cost){
            cout<<"Please ensure you enter only numeric values for the cost per night.\nEnter your new choice: ";
        }else{
            cout<<"The price is less than £0. Please enter a value above £0: ";
        }
        cin>>cost;
    }
    return cost;
}

int get_room_number(){
    int room_number;
    cout<<"Please enter the room number you wish to view: ";
    cin >> room_number;

    while(check_if_room_exists(room_number) == false){
        // Taken from StackOverflow to avoid endless loop: https://stackoverflow.com/questions/19521320/why-do-i-get-an-infinite-loop-if-i-enter-a-letter-rather-than-a-number
        cin.clear();
        cin.ignore(numeric_limits<streamsize>::max(), '\n');
        // End of code taken from StackOverflow
        if(check_if_room_exists(room_number) == false){
            cout<<"That room doesn't exist enter a new one: ";
        }

        cin>>room_number;
    }
    return room_number;
}

void delete_room(int room_number){
    remove((to_string(room_number) + ".txt").c_str());
}

这是general_functions.hpp文件：

#ifndef general_functions_hpp
#define general_functions_hpp

#include <stdio.h>
using namespace std;

bool check_if_room_exists(int);
int get_new_room_number();
int get_cost_per_night();
int get_room_number();
void delete_room(int);
#endif

最后，这就是我将头文件导入main.cpp文件的方式：

#include "general_functions.hpp"

这会导致出现以下错误：

Undefined symbols for architecture x86_64:
  "delete_room(int)", referenced from:
      single_room_manager(SingleRoom) in main-f8f1e8.o
  "get_room_number()", referenced from:
      _main in main-f8f1e8.o
  "get_cost_per_night()", referenced from:
      single_room_manager(SingleRoom) in main-f8f1e8.o
      create_single_room() in main-f8f1e8.o
  "get_new_room_number()", referenced from:
      single_room_manager(SingleRoom) in main-f8f1e8.o
      create_single_room() in main-f8f1e8.o
  "login()", referenced from:
      _main in main-f8f1e8.o
ld: symbol(s) not found for architecture x86_64

从我所做的研究来看，我认为这是由于函数的定义与它们的实际情况不匹配造成的，但是据我所见，它们匹配并且不应该引起任何问题。

帮助将不胜感激！

谢谢

标签： c++