Practice C++ functor??

functional.cc

#include <iostream>

int add1(int x) {
  return ++x;
}

int double2(int x) {
  return 2 * x;
}

int tentimes(int (*func)(int), int p) {
  int x = 0;
  for (int i = 0; i < 10; ++i) {
    x += func(p);
  }
  return x;
}

int main(int argc, char** argv) {
  std::cout << tentimes(add1, 2) << std::endl;
  std::cout << tentimes(double2, 2) << std::endl;
  return 0;
}