error when trying to link functions in C++

Asked Mar 17 '22 at 19:24

Active Mar 17 '22 at 19:38

Viewed 28 times

here is my code I get an error everytime I run it saying undefined reference to Maths::add I am using VScode with the code runner extension the command that they provide is cd "c:\Users\sethz\OneDrive\Desktop\G++" ; if ($?) { g++ main.cpp -o main } ; if ($?) { .\main }

main.cpp

#include <iostream>
#include "maths.hpp"
using namespace std;

int main()
{
    Maths maths;
    maths.add(5, 7);
}

maths.hpp

#ifndef MATHS_HPP
#define MATHS_HPP

class Maths
{
public:
    void add(float num1, float num2);
};
#endif

maths.cpp

#include "maths.hpp"
#include <iostream>
using namespace std;

void Maths::add(float num1, float num2)
{
    cout << num1 + num2;
}

Can somebody please tell me how to fix it if you know how because I've been trying to header files in C++

edited Mar 17 '22 at 19:38

asked Mar 17 '22 at 19:24

Seth Israel

1

You probably missed to link maths.cpp, how does your compiler command look? – πάντα ῥεῖ Mar 17 '22 at 19:29
1

[Likely the relevant answer of the dupe](https://stackoverflow.com/a/12574400/962089) – chris Mar 17 '22 at 19:33
that didnt solve my problem – Seth Israel Mar 17 '22 at 19:35
1

ive edited the question to be more specific – Seth Israel Mar 17 '22 at 19:38
2

It does answer the question, and @chris 's comment points you at the correct answer. `g++ main.cpp -o main` instructs the compiler to compile and link only main.cpp. That instruction needs to be `g++ main.cpp maths.cpp -o main`. – user4581301 Mar 17 '22 at 19:43
1

Note that VS Code can be configured to be much smarter than this, but that's something I'll have to leave to people who know how to do it correctly. – user4581301 Mar 17 '22 at 19:45

error when trying to link functions in C++

0 Answers0