How to Resolve an Undefined Reference Error in C++ When Using SparseMatrix?

[subwaybusker]

#include <iostream>
#include "recommender.h"
#include <stdio.h>
#include "sparsematrix.h"
using namespace std;

#ifndef RECOMMENDER_H
#define RECOMMENDER_H

class Recommender  {
    private:
        SparseMatrix* ratings;  // pointer to sparse matrix containing ratings
        char** movieNames;  // array of strings containing movie names
        int numUsers;
        int numMovies;
        int numRatings;

    public:
        // ============= FUNCTIONS TO BE IMPLEMENTED =============
        Recommender(char* filename);
        ~Recommender();

        void setNumUsers(int a) { numUsers = a; };
        void setNumMovies(int a) { numMovies = a; };
        void setNumRatings(int a) { numRatings = a; };

        char* getMovieName(int movieID);
        int getNumMovies();

        void sortMoviesByAvgRating(int order, int** sortedMovieIDs);
        float computeMovieSimilarity(int movieID1, int movieID2);
        void sortMoviesBySimilarity(int movieID, int order, int** sortedMovieIDs);
        // ========================================================
};




#endif

SparseMatrix* ratings = new SparseMatrix(numUsers, numMovies);

I'm also getting an "undefined reference error" to the SparseMatrix class in this Recommender file even though I included the header file for SparseMatrix

 

[Valkarie]

.Here is the error message:/tmp/ccVzjFxn.o: In function `Recommender::Recommender(char*)':recommender.cpp:(.text+0x54): undefined reference to `SparseMatrix::SparseMatrix(int, int)'collect2: error: ld returned 1 exit statusmake: *** [recommender] Error 1</code>The problem is that you are not including the implementation of the SparseMatrix class.You need to include both the header and implementation files for the SparseMatrix class in your Recommender.cpp file.

 

[Mene]

. It's possible that the header file is not properly linked to the implementation file, or that there is an error in the implementation of the SparseMatrix class. I would suggest double checking the implementation of the SparseMatrix class and ensuring that it is properly linked to the header file in the Recommender class. It may also be helpful to run a debugger to identify the specific source of the error.