When I run the example of tutorial, the clang3.2 give me warning like following.
opencv2/ml/ml.hpp:863:18: note: hidden overloaded virtual function 'CvDTree::train' declared here virtual bool train( CvMLData* trainData, CvDTreeParams params=CvDTreeParams() );
I check the declaration of the header file "ml.hpp"
The derived classes of CvDTree--CvBoostTree and CvForestTree declare an interfaces like this
virtual bool train( CvDTreeTrainData* trainData,
const CvMat* subsample_idx, CvBoost* ensemble );
But the signature of the CvDTree are
virtual bool train( CvDTreeTrainData* trainData, const CvMat* subsampleIdx );
Apparently, this is not override nor overload but hiding, is this the intention of the library?
example :
#include <iostream>
class base
{
public:
virtual void fun() { std::cout<<"base fun"<<std::endl; }
virtual void output(int, int, int) { std::cout<<"base output"<<std::endl;}
//print and print(int) are overload
void print() { std::cout<<"print"<<std::endl; }
void print(int) {std::cout<<"print 2"<<std::endl;}
};
class derived : public base
{
public:
virtual void fun() { std::cout<<"derived fun"<<std::endl; } //override
virtual void output(int, int) { std::cout<<"derived output"<<std::endl;} //hide the output of base class
};
int main()
{
std::unique_ptr<base> base_class(new base);
std::unique_ptr<base> derive_class(new derived);
base_class->fun();
base_class->output(0, 0, 0);
base_class->print();
base_class->print(0);
derive_class->fun();
derive_class->output(0, 0, 0); //"base output"
//derive_class->output(0, 0); //compile time error, because the output of derived
//class hide the function of the base class
derived derive_class_2;
derive_class_2.output(0, 0); //output "derived output"
//derive_class_2.output(0, 0, 0); //compile time error, because the output of derived
//class hide the function of the base class
return 0;
}
if you want to know more details, please check "exceptional c++ item 21", the book show us how to classify override, overload and hide in depth.
