Question

I am trying to call another function, foo(), in the Raw class from main.cpp but I keep on getting this error and I do not understand what is wrong with my code. I am working in C++, and I am using the QT framework. I am new to this language and framework.

Error:
LNK2019: unresolved external symbol “public:void __thiscall RAW::foo(void)” (?foo@Raw@@QAEXXZ) referenced in function_main. File not found:main.obj

main.cpp

#include "raw.h"

using namespace std;


int main(int, char*)
{
    Raw newRaw;
    newRaw.foo();

    return 0;
}

raw.cpp

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

using namespace std;

void foo()
{
    cout << "hi\n";
}

Raw::Raw()
{
    cout << "raw\n";
}

raw.h

#ifndef RAW_H
#define RAW_H

class Raw
{
public:
    Raw();
    void foo();
};

#endif // RAW_H

Answer 1

In raw.cpp you have to define foo like this:

void Raw::foo()
{
    cout << "hi\n";
}

You have to put Raw:: so that the compiler knows that this is the class member function foo and not some other independent function.