[SOLVED] C++ errors

MTK358 · 01-16-2011, 11:08 AM

When compiling my project I get these errors:

Code:

$ make
[ 12%] Building CXX object src/CMakeFiles/lang.dir/IntegerPrimitive.cpp.o
/home/michael/lang/src/IntegerPrimitive.hpp: In member function ‘AbstractObject* Func_print::call(std::vector<AbstractObject*>)’:
/home/michael/lang/src/IntegerPrimitive.hpp:16:9: error: ‘int IntegerPrimitive::value’ is private
/home/michael/lang/src/IntegerPrimitive.cpp:7:87: error: within this context
/home/michael/lang/src/IntegerPrimitive.cpp: In constructor ‘IntegerPrimitive::IntegerPrimitive(std::string&)’:
/home/michael/lang/src/IntegerPrimitive.cpp:14:51: error: no matching function for call to ‘IntegerPrimitive::set(std::string, Func_print*)’
/home/michael/lang/src/Scope.hpp:16:25: note: candidate is: virtual void Scope::set(std::string&, AbstractObject*)
make[2]: *** [src/CMakeFiles/lang.dir/IntegerPrimitive.cpp.o] Error 1
make[1]: *** [src/CMakeFiles/lang.dir/all] Error 2
make: *** [all] Error 2

I can't figure them out, the code looks perfectly fine to me. In case it helps, this is the hierarchy of the classes:

Code:

AbstractObject
    Scope
        IntegerPrimitive
    AbstractFunction
        Func_print (in IntegerPrimitive's .cpp file)

If you need the code, I can attach a compressed archive to a later post.

Sergei Steshenko · 01-16-2011, 11:41 AM

Quote:

Originally Posted by MTK358

When compiling my project I get these errors:

Code:

$ make
[ 12%] Building CXX object src/CMakeFiles/lang.dir/IntegerPrimitive.cpp.o
/home/michael/lang/src/IntegerPrimitive.hpp: In member function ‘AbstractObject* Func_print::call(std::vector<AbstractObject*>)’:
/home/michael/lang/src/IntegerPrimitive.hpp:16:9: error: ‘int IntegerPrimitive::value’ is private
/home/michael/lang/src/IntegerPrimitive.cpp:7:87: error: within this context
/home/michael/lang/src/IntegerPrimitive.cpp: In constructor ‘IntegerPrimitive::IntegerPrimitive(std::string&)’:
/home/michael/lang/src/IntegerPrimitive.cpp:14:51: error: no matching function for call to ‘IntegerPrimitive::set(std::string, Func_print*)’
/home/michael/lang/src/Scope.hpp:16:25: note: candidate is: virtual void Scope::set(std::string&, AbstractObject*)
make[2]: *** [src/CMakeFiles/lang.dir/IntegerPrimitive.cpp.o] Error 1
make[1]: *** [src/CMakeFiles/lang.dir/all] Error 2
make: *** [all] Error 2

I can't figure them out, the code looks perfectly fine to me. In case it helps, this is the hierarchy of the classes:

Code:

AbstractObject
    Scope
        IntegerPrimitive
    AbstractFunction
        Func_print (in IntegerPrimitive's .cpp file)

If you need the code, I can attach a compressed archive to a later post.

Code:

/home/michael/lang/src/IntegerPrimitive.hpp:16:9: error: ‘int IntegerPrimitive::value’ is private
/home/michael/lang/src/IntegerPrimitive.cpp:7:87: error: within this context

- looks like you are trying to use a private member directly rather than trough a public method belonging to the same class.

MTK358 · 01-16-2011, 11:50 AM

Code:

#ifndef __IntegerPrimitive_hpp_INCLUDE_GUARD__
#define __IntegerPrimitive_hpp_INCLUDE_GUARD__

#include "Scope.hpp"
#include "AbstractFunction.hpp"
#include <cstdlib>
#include <string>
#include <cstdio>

class IntegerPrimitive : public Scope
{
public:
    IntegerPrimitive(std::string &str);
    
private:
    int value;                           // this is the error you pointed out
};

#endif // #ifndef __IntegerPrimitive_hpp_INCLUDE_GUARD__

What's wrong with defining a private variable, how's that an error?

Aquarius_Girl · 01-16-2011, 12:11 PM

Quote:

Originally Posted by MTK358

What's wrong with defining a private variable, how's that an error?

Defining a private variable is not the problem, accessing it "directly" IS. You need to read up on the use of making a variable 'private'. Private variables can be accessed only by the members of the class in question, nothing else.

MTK358 · 01-16-2011, 12:37 PM

OK, I fixed it.

Now what about this:

Code:

/home/michael/lang/src/IntegerPrimitive.cpp: In constructor ‘IntegerPrimitive::IntegerPrimitive(std::string&)’:
/home/michael/lang/src/IntegerPrimitive.cpp:14:51: error: no matching function for call to ‘IntegerPrimitive::set(std::string, Func_print*)’
/home/michael/lang/src/Scope.hpp:16:25: note: candidate is: virtual void Scope::set(std::string&, AbstractObject*)

Sergei Steshenko · 01-16-2011, 01:13 PM

Quote:

Originally Posted by MTK358

OK, I fixed it.

Now what about this:

Code:

/home/michael/lang/src/IntegerPrimitive.cpp: In constructor ‘IntegerPrimitive::IntegerPrimitive(std::string&)’:
/home/michael/lang/src/IntegerPrimitive.cpp:14:51: error: no matching function for call to ‘IntegerPrimitive::set(std::string, Func_print*)’
/home/michael/lang/src/Scope.hpp:16:25: note: candidate is: virtual void Scope::set(std::string&, AbstractObject*)

See the item in red - as before.

MTK358 · 01-16-2011, 01:30 PM

IntegerPrimitive is a subclass of Scope and Func_print is a subclass of AbstractObject.

And set() is public.

Sergei Steshenko · 01-16-2011, 01:42 PM

Quote:

Originally Posted by MTK358

IntegerPrimitive is a subclass of Scope and Func_print is a subclass of AbstractObject.

And set() is public.

Does the function signature (of 'IntegerPrimitive::set') match ? The compiler says it doesn't.

MTK358 · 01-16-2011, 01:45 PM

There is no IntegerPrimitive::set().

Sergei Steshenko · 01-16-2011, 01:49 PM

Quote:

Originally Posted by MTK358

There is no IntegerPrimitive::set().

Then, what is the question ? I.e. how can the compiler use a function which doesn't exist ?

MTK358 · 01-16-2011, 01:51 PM

IntegerPrimitive is derived from Scope, which has the set() function.

Sergei Steshenko · 01-16-2011, 01:55 PM

Quote:

Originally Posted by MTK358

IntegerPrimitive is derived from Scope, which has the set() function.

Again, does the signature match ?

MTK358 · 01-16-2011, 01:58 PM

Here is the signature:

Code:

virtual void set(std::string &name, AbstractObject *value);

Here is the call that causes the error:

Code:

set(std::string("print"), new Func_print(this));

Sergei Steshenko · 01-16-2011, 02:03 PM

Quote:

Originally Posted by MTK358

Here is the signature:

Code:

virtual void set(std::string &name, AbstractObject *value);

Here is the call that causes the error:

Code:

set(std::string("print"), new Func_print(this));

So, did you implement the function marked virtual in the derived class ?

johnsfine · 01-16-2011, 02:29 PM

Quote:

Originally Posted by MTK358

this is the hierarchy of the classes:

Code:

AbstractObject
    Scope
        IntegerPrimitive
    AbstractFunction
        Func_print (in IntegerPrimitive's .cpp file)

Is AbstractFunction a public base class of Func_print?
Is AbstractObject a public base class of AbstractFunction?

Code:

no matching function for call to ‘IntegerPrimitive::set(std::string, Func_print*)

What declarations of set() are in IntegerPrimitive? Any chance such declaration hides the base class declaration of set() that you want?

Quote:

Originally Posted by Sergei Steshenko

So, did you implement the function marked virtual in the derived class ?

Missing that would give a different error message (if it were an error at all).