No Default Constructor available problem

[krishnasamy]

Hi,

I have a sq.h include file which containing following code,

[CODE=cpp]struct FRSDK_SHARED SampleQuality
{
SampleQuality( bool enrollmentOk, bool verificationOk, float q,
const std::string& hint);
const bool goodForEnrollme nt;
const bool goodForVerifica tion;
const float quality;
const std::string hint;
};

class FRSDK_SHARED SampleEvaluator
{
public:
SampleEvaluator ( const Configuration&) ;
SampleEvaluator ( const SampleEvaluator &);
SampleEvaluator & operator=( const SampleEvaluator &);
~SampleEvaluato r();

SampleQuality evaluate(/** the Image to evaluate */
const Image& img,
/** location of the eyes */
const Eyes::Location& eloc);

private:
class Implementation;
CountedPtr<Impl ementation> imp;
};

}

#endif[/CODE]

I include the sq.h file and I have write the following code in my CPP file,

FRsdk::Eyes::Lo cation eyesLoc = eyesLocations.f ront();
FRsdk::SampleQu ality sampleQuality = FRsdk::SampleEv aluator::evalua te( img, eyesLoc);

The following error are come,

'FRsdk::SampleQ uality' : no appropriate default constructor available
'FRsdk::SampleE valuator::evalu ate' : illegal call of non-static member function

what is the problem?

[Ganon11]

For the first error, the error text says it all. You are trying to use the default constructor somewhere, but you don't have one. Either find out where you're instantiating a StructQuality object without passing it the proper arguments, or write a default constructor for the struct (This can be as easy as giving it default values in the already-defined constructor).

[krishnasamy]

For the first error, the error text says it all. You are trying to use the default constructor somewhere, but you don't have one. Either find out where you're instantiating a StructQuality object without passing it the proper arguments, or write a default constructor for the struct (This can be as easy as giving it default values in the already-defined constructor).

Thanks for your reply.

I am a new for vc++. So how I write a default constructor for the struct.

[Ganon11]

A default constructor is a constructor that has no arguments. So you would write yours like

[CODE=cpp]StructQuality:: StructQuality(/*no arguments here, see? */) {
// Any relevant code here.
// You may want to assign the member variables some default value.
// This may not be a good idea, though, since a few of your member variables are const.
// Anyway, this code needs to do whatever you need to do in order to set the variables up properly like you do in the other constructor.
}[/CODE]

[weaknessforcats]

I am a new for vc++. So how I write a default constructor for the struct.

Without blowing your mind, there really aren't classes in C++. The underlying implementation of a class is a struct. This goes clear back to C where a struct is the only way to group data members together. C++ is a replacement for C it carries the struct also.

The only difference between a struct and a class is that the default access for a struct is public whereas the default access fo a class is private. And that's it.

If you specify public/private/protected for each member of your struct, the result will be identical to a class:
[code=cpp]
struct Date
{
private:
int month;
int day;
int year;
public:
Date(); //default constructor
Data(const Date& d); //copy constructor
~Data(); //destructor
void ChangeDate(int m, int d, int y);
};
//is identical to:
class Date
{
private:
int month;
int day;
int year;
public:
Date(); //default constructor
Data(const Date& d); //copy constructor
~Data(); //destructor
void ChangeDate(int m, int d, int y);
};
[/code]

[krishnasamy]

A default constructor is a constructor that has no arguments. So you would write yours like

[CODE=cpp]StructQuality:: StructQuality(/*no arguments here, see? */) {
// Any relevant code here.
// You may want to assign the member variables some default value.
// This may not be a good idea, though, since a few of your member variables are const.
// Anyway, this code needs to do whatever you need to do in order to set the variables up properly like you do in the other constructor.
}[/CODE]

----
Thanks for your reply.

I have changed my code as,
int NewDemoDll::Eye Finder()
{
FRsdk::SampleQu ality()
{
}
}

But the same errors are occur,
error C2143: syntax error : missing ';' before '{'
error C2512: 'FRsdk::SampleQ uality::SampleQ uality' : no appropriate default constructor available

Please give your kind of suggestion.

[krishnasamy]

----
Thanks for your reply.

I have changed my code as,
int NewDemoDll::Eye Finder()
{
FRsdk::SampleQu ality()
{
}
}

But the same errors are occur,
error C2143: syntax error : missing ';' before '{'
error C2512: 'FRsdk::SampleQ uality::SampleQ uality' : no appropriate default constructor available

Please give your kind of suggestion.

----
I have changed my code as follows,

FRsdk::Eyes::Lo cation eyesLoc = eyesLocations.f ront();

FRsdk::SampleEv aluator eve;

FRsdk::SampleQu ality sampleQuality =eve.evaluate( img, eyesLoc);

Now I have not compilation error but Link errors are come,

Such as,

NewDll error LNK2019: unresolved external symbol "__declspec(dll import) public: __thiscall FRsdk::SampleEv aluator::Sample Evaluator(void) " (__imp_??0Sampl eEvaluator@FRsd k@@QAE@XZ) referenced in function "public: static int __cdecl NewDll::NewDemo Dll::EyeFinder( void)" (?EyeFinder@New DemoDll@NewDll@ @SAHXZ)
NewDll fatal error LNK1120: 1 unresolved externals


Please give the solution to this problem.

[krishnasamy]

----
I have changed my code as follows,

FRsdk::Eyes::Lo cation eyesLoc = eyesLocations.f ront();

FRsdk::SampleEv aluator eve;

FRsdk::SampleQu ality sampleQuality =eve.evaluate( img, eyesLoc);

Now I have not compilation error but Link errors are come,

Such as,

NewDll error LNK2019: unresolved external symbol "__declspec(dll import) public: __thiscall FRsdk::SampleEv aluator::Sample Evaluator(void) " (__imp_??0Sampl eEvaluator@FRsd k@@QAE@XZ) referenced in function "public: static int __cdecl NewDll::NewDemo Dll::EyeFinder( void)" (?EyeFinder@New DemoDll@NewDll@ @SAHXZ)
NewDll fatal error LNK1120: 1 unresolved externals


Please give the solution to this problem.

-----------

I have solved that problem.

Thank you for your kind of Suggestion.