issues importing c++ class

Question

I have a class A(has a.h and a.cpp file) which I am importing to main.cpp. I created an object of the class A and trying to access the methods in class I get undefined reference to `A::Reset(unsigned int*, unsigned int*)'.

I am not sure whats wrong in my code

//a.h

#ifndef _A_H_
#define _A_H_

class A
{

    public:

        A();
        void Reset();
};
#endif

//a.cpp:

#include "A.h"

A::A()
{

    Reset();
}


void A::Reset()
{

}

//main.cpp

#include "A.h"
int main(int argc, const char * argv[])
{

    A *aObj = new A;
    aObj->Reset();
}

Any help would be appreciated.

`_A_H_` is [bad](http://stackoverflow.com/questions/228783/what-are-the-rules-about-using-an-underscore-in-a-c-identifier). — chris, Apr 28 '13 at 07:32
What compilation commands are you using? And "import" is not the right wording for C++ .... — Basile Starynkevitch, Apr 28 '13 at 11:20

Houssam Badri · Answer 1 · 2013-04-28T07:26:22.793

3

Correct you main.cpp file as this:

#include "a.h" 

int main(int argc, const char * argv[])
{

    A *aObj = new A; 
    aObj->Reset();

/*
or
   A aObj;
   aObj.Reset()
*/
}

edited Apr 28 '13 at 07:26

answered Apr 28 '13 at 07:19

Houssam Badri

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Sorry it was a copy mistake. I had a star. – pa12 Apr 28 '13 at 07:46

NPE · Answer 2 · 2013-04-28T11:37:15.553

1

First of all, you need to compile and link both A.cpp and main.cpp when building the executable. For example:

g++ -o main A.cpp main.cpp

As to the missing compare() function, make sure that it's declared in A.h:

class A {
   ...
   int compare(unsigned int*, unsigned int*);
}

and defined in A.cpp:

int A::compare(unsigned int*, unsigned int*) {
   ...
}

edited Apr 28 '13 at 11:37

answered Apr 28 '13 at 07:09

NPE

486,780
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He does not need to include a.cpp file – Houssam Badri Apr 28 '13 at 07:20
It should be `g++ -g -Wall a.cpp main.cpp -o main` – Basile Starynkevitch Apr 28 '13 at 11:20

issues importing c++ class

2 Answers2