C++, generic programming and virtual functions. How do I get what I want?
- by carleeto
This is what I would like to do using templates:
struct op1
{
virtual void Method1() = 0;
}
...
struct opN
{
virtual void MethodN() = 0;
}
struct test : op1, op2, op3, op4
{
virtual void Method1(){/*do work1*/};
virtual void Method2(){/*do work2*/};
virtual void Method3(){/*do work3*/};
virtual void Method4(){/*do work4*/};
}
I would like to have a class that simply derives from a template class that provides these method declarations while at the same time making them virtual. This is what I've managed to come up with:
#include <iostream>
template< size_t N >
struct ops : ops< N - 1 >
{
protected:
virtual void DoStuff(){ std::cout<<N<<std::endl; };
public:
template< size_t i >
void Method()
{ if( i < N ) ops<i>::DoStuff(); }
//leaving out compile time asserts for brevity
}
struct test : ops<6>
{
};
int main( int argc, char ** argv )
{
test obj;
obj.Method<3>(); //prints 3
return 0;
}
However, as you've probably guessed, I am unable to override any of the 6 methods I have inherited. I'm obviously missing something here. What is my error? No, this isn't homework. This is curiosity.
