VsCode，C ++-铛：错误：链接器命令失败，退出代码为1（使用-v查看调用）

Question

我正在尝试运行以下c ++文件，但是在编译时遇到了一些错误。我在MacOS上使用VSCode，并尝试进行搜索，但是我仍然被卡住，不知道是什么问题。

File.cpp文件：

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
namespace sdds{



FILE* fptr;       

// opens the data file and returns true is successful
bool openFile(const char filename[]) {
   fptr = fopen(filename, "r");
   return fptr != NULL;
}

// closes the data file
void closeFile() {
   if (fptr) fclose(fptr);
}

// reads the title of the movie from the global fptr File pointer
// returns true if successful
bool readTitle(char title[]) {
   return fscanf(fptr, "%[^(](", title) == 1;
}

// reads the year of the movie from the global fptr File pointer
// returns true if successful
bool readYear(int* year) {
   return fscanf(fptr, "%d)", year) == 1;
}

// reads the year of the movie from the global fptr File pointer
// returns true if successful
bool readMovieRating(char rating[]) {
   return fscanf(fptr, " %[^|]|", rating) == 1;
}

// reads the duration of the movie from the global fptr File pointer
// returns true if successful
bool readDuration(int* duration) {
   return fscanf(fptr, "%d|", duration) == 1;
}

// reads the genras of the movie from the global fptr File pointer
// returns true if successful
bool readGenres(char genre[][11]) {
   char genres[256];
   int gi = 0; //genres index;
   int i = 0;// genre[i] index
   int j = 0;// genre[i][j] index
   bool res = fscanf(fptr, " %[^|]|", genres);
   if (res) { //spreading csv to array of strings
      res = false;
      while (genres[gi]) {
         if (genres[gi] != ',') {
            genre[i][j++] = genres[gi++];
            res = true;
         }
         else {
            genre[i][j] = '\0';
            i++;
            gi++;
            j = 0;
         }
      }
   }
   genre[i++][j] = '\0';
   genre[i][0] = '\0'; // NULL terminating the array of strings
   return res;
}

// reads the consumerRating of the movie from the global fptr File pointer
// returns true if successful
bool readConsumerRating(float* rating) {
   return fscanf(fptr, "%f\n", rating) == 1;
}
}

当我尝试使用g ++进行编译时，出现以下错误：

clang: error: linker command failed with exit code 1 (use -v to see invocation)

当我尝试运行以下Movie.cpp文件时：

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstring>
#include <cstdio>
#include "File.h"
#include "Movie.h"
using namespace std;

namespace sdds{


Movie movies[50];

// loads all the moves into the global array of structures.
bool loadMovies() {
   Movie mv;
   int mnum = 0; // number of movies read
   bool ok = true;
   if (openFile("movies.dat")) {
      while (ok && mnum < 50) {
         ok = readTitle(mv.m_title) &&
            readYear(&mvx.m_year) &&
            readMovieRating(mv.m_rating) &&
            readDuration(&mv.m_duration) &&
            readGenres(mv.m_genres) &&
            readConsumerRating(&mv.m_consumerRating);
         if (ok) movies[mnum++] = mv;
      }
      closeFile();
   }
   return mnum == 50;
}

// returns true is the genre arg is substring of any of the
// genres of the target of the mvp (Movie*) arg.
bool hasGenre(const Movie* mvp, const char genre[]) {
   int i = 0;
   bool found = false;
   while (!found && mvp->m_genres[i][0]) {
      if (strstr(mvp->m_genres[i++], genre)) {
         found = true;
      }
   }
   return found;
}

// displays the movie info
void displayMovie(const Movie* mvp) {
   int i = 1;
   cout << mvp->m_title << " [" << mvp->m_year << "], "
      << mvp->m_rating << ", duration: " << mvp->m_duration << " minutes, Rating: " << mvp->m_consumerRating << "/10" << endl << "    (" << mvp->m_genres[0];
   while (mvp->m_genres[i][0]) {
      cout << ", " << mvp->m_genres[i++];
   }
   cout << ")" << endl;
}

// displays all the movies containing the genre arg
void displayMoviesWithGenre(const char genre[]) {
   int i, j;
   for (i = 0, j = 1; i < 50; i++) {
      if (hasGenre(&movies[i], genre)) {
         cout << j++ << "- ";
         displayMovie(&movies[i]);
      }
   }
   if (j == 1) {
      cout << "No match found for: " << genre << endl;
   }
}


}

我收到以下错误：

Movie.cpp:23:8: error: use of undeclared identifier 'openFile'
   if (openFile("movies.dat")) {
       ^
Movie.cpp:25:15: error: use of undeclared identifier 'readTitle'
         ok = readTitle(mv.m_title) &&
              ^
Movie.cpp:26:13: error: use of undeclared identifier 'readYear'
            readYear(&mv.m_year) &&
            ^
Movie.cpp:27:13: error: use of undeclared identifier 'readMovieRating'
            readMovieRating(mv.m_rating) &&
            ^
Movie.cpp:28:13: error: use of undeclared identifier 'readDuration'
            readDuration(&mv.m_duration) &&
            ^
Movie.cpp:29:13: error: use of undeclared identifier 'readGenres'
            readGenres(mv.m_genres) &&
            ^
Movie.cpp:30:13: error: use of undeclared identifier 'readConsumerRating'
            readConsumerRating(&mv.m_consumerRating);
            ^
Movie.cpp:33:7: error: use of undeclared identifier 'closeFile'
      closeFile();
      ^
8 errors generated.
g++ Movie.cpp
Movie.cpp:23:8: error: use of undeclared identifier 'openFile'
   if (openFile("movies.dat")) {
       ^
Movie.cpp:25:15: error: use of undeclared identifier 'readTitle'
         ok = readTitle(mv.m_title) &&
              ^
Movie.cpp:26:13: error: use of undeclared identifier 'readYear'
            readYear(&mv.m_year) &&
            ^
Movie.cpp:27:13: error: use of undeclared identifier 'readMovieRating'
            readMovieRating(mv.m_rating) &&
            ^
Movie.cpp:28:13: error: use of undeclared identifier 'readDuration'
            readDuration(&mv.m_duration) &&
            ^
Movie.cpp:29:13: error: use of undeclared identifier 'readGenres'
            readGenres(mv.m_genres) &&
            ^
Movie.cpp:30:13: error: use of undeclared identifier 'readConsumerRating'
            readConsumerRating(&mv.m_consumerRating);
            ^
Movie.cpp:33:7: error: use of undeclared identifier 'closeFile'
      closeFile();