Error creating a class in C

Question

I've some error on this class construction,

cwrapper.h

#include "SimpleCLM.h"

using namespace std;
using namespace cv;

class A{
public:
    A();
    ~A();
    met1();
};

void *A_init();
A_m1(void *p);

cwrapper.c

#include "cwrapper.h"

using namespace std;
using namespace cv;

void *A_init()
{
    A *p = new A;
    return (void *)p;
}

A_m1(void *p)
{
    return p->met1();
}

A::met1()
{
    return begin();
}

begin is a function in SimpleCLM.h.

Here is the errors on make,

In file included from /home/samuel/Desktop/matlab_cpp/cwrapper.h:1,
                 from /home/samuel/Desktop/matlab_cpp/cwrapper.c:1:
/home/samuel/Desktop/matlab_cpp/SimpleCLM.h:2: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘begin’
In file included from /home/samuel/Desktop/matlab_cpp/cwrapper.c:1:
/home/samuel/Desktop/matlab_cpp/cwrapper.h:3: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘namespace’
/home/samuel/Desktop/matlab_cpp/cwrapper.h:4: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘namespace’
/home/samuel/Desktop/matlab_cpp/cwrapper.h:6: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘A’
/home/samuel/Desktop/matlab_cpp/cwrapper.h:14: warning: data definition has no type or storage class
/home/samuel/Desktop/matlab_cpp/cwrapper.c:3: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘namespace’
/home/samuel/Desktop/matlab_cpp/cwrapper.c:4: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘namespace’
/home/samuel/Desktop/matlab_cpp/cwrapper.c: In function ‘A_init’:
/home/samuel/Desktop/matlab_cpp/cwrapper.c:8: error: ‘A’ undeclared (first use in this function)
/home/samuel/Desktop/matlab_cpp/cwrapper.c:8: error: (Each undeclared identifier is reported only once
/home/samuel/Desktop/matlab_cpp/cwrapper.c:8: error: for each function it appears in.)
/home/samuel/Desktop/matlab_cpp/cwrapper.c:8: error: ‘p’ undeclared (first use in this function)
/home/samuel/Desktop/matlab_cpp/cwrapper.c:8: error: ‘new’ undeclared (first use in this function)
/home/samuel/Desktop/matlab_cpp/cwrapper.c:8: error: expected ‘;’ before ‘A’
/home/samuel/Desktop/matlab_cpp/cwrapper.c: In function ‘A_m1’:
/home/samuel/Desktop/matlab_cpp/cwrapper.c:14: warning: dereferencing ‘void *’ pointer
/home/samuel/Desktop/matlab_cpp/cwrapper.c:14: error: request for member ‘met1’ in something not a structure or union
/home/samuel/Desktop/matlab_cpp/cwrapper.c: At top level:
/home/samuel/Desktop/matlab_cpp/cwrapper.c:17: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘:’ token
make[2]: *** [CMakeFiles/cwrapper.dir/cwrapper.c.o] Error 1
make[1]: *** [CMakeFiles/cwrapper.dir/all] Error 2
make: *** [all] Error 2

A lot more problems in this code than just writing it in the wrong language. — Crowman, May 19 '14 at 13:59

score 3 · Accepted Answer · answered May 19 '14 at 13:35

3

It is impossible to create a class in C; you would have to tell the compiler somehow that you want to compile C++.

answered May 19 '14 at 13:35

Codor

17,447
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1

so changing the name of the wrapper file to `cwrapper.cpp` would solve this? – SamuelNLP May 19 '14 at 13:36
Might be; I'm not too deelpy in to C/C++. What compiler are you using? – Codor May 19 '14 at 13:37
If you are using MacOSX or Linux use .cc not .cpp – Ahmed Masud May 19 '14 at 13:37
I've always used .cpp in linux. I'm using gcc 4.4.7 – SamuelNLP May 19 '14 at 13:42
2

@Ahmed Masud whats wrong with .cpp? never heard of one should avoid that file extension. – dhein May 19 '14 at 13:42
Since you're using `make`, changing the extension will do the trick – slugonamission May 19 '14 at 14:03
2

@SamuelNLP changing extension will not fix your bad code which has a lot more problemes. please read a good c++ book. its hopeless to expect to learn c++ from putting code of this quality at SO and hope people will fix it. – vlad_tepesch May 19 '14 at 14:45
@Zaibis cpp is actually C preprocessor extension which is why .cc is used on most *nix platforms – Ahmed Masud May 19 '14 at 15:39
@AhmedMasud please post some references. cpp means c plus plus and is widely used for c++ code files. – vlad_tepesch May 19 '14 at 15:59
deeply and exhaustively discussed at http://stackoverflow.com/questions/1545080/correct-c-code-file-extension-cc-vs-cpp – Ahmed Masud May 19 '14 at 16:40
I actually stand corrected, my brain must have gone off somewhere. .cpp is fine as an extension. http://labor-liber.org/en/gnu-linux/development/extensions is a good source – Ahmed Masud May 19 '14 at 16:44

Error creating a class in C

1 Answers1