Linker error when passing argument with int const & type

[ziyet]

Hi I wrote a function that takes csv file, read its (numeric) content and convert it into 2darray and return the pointer to this array. But when I pass in int const & row, int const & col, it gives the following linker error:

Undefined symbols for architecture x86_64:
"csv2array(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, unsigned long, unsigned long)", referenced from:
_main in csv_to_array-80e056.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Here is my code:

  
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
using namespace std;

double** csv2array(string filename, const size_t row, const size_t col);
/*    This function converts csv file into 2-d array
 *    used to convert numpy 2d array into c++ array
 *    filename -- csv file containing 2d matrix
 *    row, col -- dimension of the matrix
 */

int main() {
    const size_t SIZE = 103; // sample size
        
    double **odM = csv2array("odMat.csv", SIZE, SIZE);
    double **Dist = csv2array("dist.csv", SIZE, SIZE);
    for (size_t i=0; i<SIZE; i++) {
        for (size_t j=0; j<SIZE; j++) {
            cout << odM[i][j] << "\t";
        }
        cout << endl;
    }
    for (size_t i=0; i<SIZE; i++) {
        delete [] odM[i];
        delete [] Dist[i]; 
    }
    delete [] odM;
    delete [] Dist;
    return 0;
}

double** csv2array(string filename, const size_t &row, const size_t &col) {
    ifstream file(filename); // associate a buffer with filename
    double **mat = new double*[row]; // note need to release in main function!
    for (size_t i=0; i<row; i++) {
        mat[i] = new double[col];
        string element;
        getline(file, element); // read a whole line into csv file, have to return string type
        if ( !file.good() )
            break;
        stringstream iss(element);
        for (size_t j=0; j<col; j++) {
            string val;
            getline(iss, val, ',');
            if ( !iss.good() )   
                break;

            stringstream convertor(val);
            convertor >> mat[i][j]; 
        }
    }
    return mat;
}

If i remove alias symbol, it compiles fine. It achieves my goal here. But I am just curious why const int & row will give such an error. Thanks in advance!

[Thomas1965]

double** csv2array(string filename, const size_t row, const size_t col);

does not match

double** csv2array(string filename, const size_t &row, const size_t &col){
//...
}

If you remove the reverences or add the reverences to your function prototype it will compile.

[ziyet]

Thanks a lot.