Pass a template method as an argument

Question

Could some one help me how to implement this code?

I need to pass a function to another function:

std::cout << process_time(Model::method1) <<         


        

Answer 1

Change your process time line with time += to:

   time += algorithm(&model,arg1);

then call it with:

std::cout << process_time([](Model* m, std::vector& v){return m->method1(v);}) << std::endl;

or in C++14:

std::cout << process_time([](Model* m, auto& v){return m->method1(v);}) << std::endl;

which leaves the choice of what kind of vector it will pass to method1 up to process_time instead of fixing it at the calling site.

Basically, this avoids dealing with pointer-to-member variables. Instead, the algorithm in process_time is just a map from Model x vector to double. This also means that we can have a non-member algorithm.

If you don't like the verbosity of the above at the call site, you can keep the changes to process_time and change the call to:

std::cout << process_time(std::ref(&Model::method1)) << std::endl;

as std::ref takes a pointer to a member function, and returns a callable object that takes a pointer-to-Model as the first argument, and std::vector& as the second. Which matches how we use it.