Function pointer to class member function

Question

I want to make function which has function pointer as a parameter.

#include 
using namespace std;

class test{

public:
    test(){};

    do         


        

Answer 1

If you want to pass a pointer to a member-function, you need to use a member-function-pointer, not a pointer for generic free functions and an object to invoke it on.

Neither is optional.

double fptr_test(test& t, double (test::*fptr)(double), double input){
    return t.*fptr(input);
}

// call like this:
fptr_test(&test::tt, 3); // Your second try