C++ constructor gives undefined reference

Question

I am moving to C++ from a Delphi scenario and I am trying to convert the projects to C++. If you look at main.cpp you can see:

#include<iostream>
#include "eqsecdeg.h"

int main() {
     
 double a, b, c;
 
 std::cin >> a;
 std::cin >> b;
 std::cin >> c;

 equations::eqSecDeg solver(a, b, c);
 std::cout << solver.getDelta();

 return 0;

}

And the file called eqsecdeg.h has this kind of content:

#ifndef EQUATIONS_H
#define EQUATIONS_H

#include<vector>
#include<complex>

namespace equations {

 //solve second degree equation
 class eqSecDeg {

  private:
   double a, b, c, delta;
   double getDelta(double a, double b, double c);
   std::vector<double> solArray;
  public:
   eqSecDeg(const double valA, const double valB, const double valC);
   double getDelta();
   std::string getDerivative();
   std::vector<double> getSolutions();
  };

  //help methods for output
  double fractionToDecimal(const std::string& value);
  std::string decimalToFraction(const double x);

}

#endif

I have read this so many times and googled a solution, but I had no luck. When I give a g++ -std=c++14 main.cpp in my linux shell I have this error:

main.cpp:(.text+0x72): undefined reference to equations::eqSecDeg::eqSecDeg(double, double, double)

main.cpp:(.text+0x7e): undefined reference to equations::eqSecDeg::getDelta() collect2: error: ld returned 1 exit status

Any idea? I really cannot understand where this code is wrong. I put the include to the header file, the correct namespace and I am creating a local object in the standard way. Any typing error?

Note: if needed this is the implementation of the header (called eqsecdeg.cpp)

`g++ -std=c++14 main.cpp` does not build eqsecdeg.cpp or link in on object containing eqsecdeg.cpp. You will have to do one of them. — user4581301, Jan 05 '17 at 00:28
and you have issues in your cpp file that probably only proves that you dont build it at all — Oleg Bogdanov, Jan 05 '17 at 00:28
this means that I have to g++ the header and it's cpp implementation? — Raffaele Rossi, Jan 05 '17 at 00:30
`g++ -std=c++14 main.cpp eqsecdeg.cpp` should be enough, though I could have the order wrong. — user4581301, Jan 05 '17 at 00:32

C++ constructor gives undefined reference

0 Answers0