Question

I am trying to use templates along with vector in my code the following way:

In my header file:

template <typename V>
void changeConfig(char option, vector <V> & arg_in){
        // ....
  }

In the source file:

vector <int> p = {4};
changeConfig('w' ,p);

And this’s the error that I get:

/include/config.h: In member function ‘void Cfconfig::changeConfig(char, std::vector<_RealType>&) [with V = int]’:

src/config_test.cpp:10:38: instantiated from here

/include/config.h:68:25: error: no match for call to ‘(int_vector {aka std::vector}) (std::vector&)’

make: *** [featureconfig_test.o_dbg] Error 1

I tried the suggestions on this thread but none of them seem to work.

C++ Templates Error: no matching function for call

Any help would be appreciated. Thanks.

Okay, I made a short snippet of my code which gives the same error:

#include <iostream>
#include <stdio.h>
#include <stdarg.h>
#include <cstdio>
#include <opencv2/opencv.hpp>
#include <string.h>
#include <math.h>
#include <complex.h>
#include <dirent.h>
#include <fstream>
#include <typeinfo> 
#include <unistd.h>
#include <stdlib.h>
#include <algorithm>
#include <array>
#include <initializer_list>
#include <vector>
#include <algorithm>


using namespace std;


template <typename V>
void changeConfig(char option, vector <V> & arg_in){

     vector<int> window = {5};
     vector<double> scale = {3};

            switch(option){
                    case 'w':                                        
                            window(arg_in);
                            break;
                    case 's':
                            scale(arg_in);
                            break;
            } 

    }


int main(){

    vector <int> p = {3};
    changeConfig<int>('w', p);

    return 0;

}

---

I compiled using :
g++ -std=c++0x test_template.cpp -o test

which gave me this error:

test_template.cpp: In function ‘void changeConfig(char, std::vector<_RealType>&) [with V = int]’:

test_template.cpp:45:33: instantiated from here

test_template.cpp:32:33: error: no match for call to ‘(std::vector) (std::vector&)’

test_template.cpp:35:33: error: no match for call to ‘(std::vector) (std::vector&)’

Answer 1

The problem is with window(arg_in); and scale(arg_in);. You are trying to call an std::vector like a function with another std::vector as an argument. I think you are trying to assign one vector to another, so just use assignment or swap.

 vector<int> window = {5};
 vector<int> scale = {3}; // Note I changed this from double to int

        switch(option){
                case 'w':                                        
                        window = arg_in; // Perhaps you meant arg_in = window
                        break;
                case 's':
                        scale = arg_in;  // Perhaps you meant arg_in = scale
                        break;
        } 

}

If you want to use vector<double> scale, use scale.assign(arg_in.begin(), arg_in.end()); instead or the other way around arg_in.assign(scale.begin(), scale.end());.