#include<iostream>

int func ()
{
  std::cout << "foo()\n"; 
  return 0;
}

void foo1 (int (*pf)()) { pf(); }
void foo2 (int (pf)()) { pf(); }
void foo3 (int pf()) { pf(); }

int main ()
{
  foo1(func);
  foo2(func);
  foo3(func);
}