#include <iostream>
#include <string>


// The C++ Programming Language, 3ed, page 524.
// Possible definition of the for_each function template. 
template <class In, class Op> Op for_each(In first, In last, Op f){
  while (first != last) f(*first++);
  return f;
}

void print_element(int i){
  std::cout << i << std::endl;
}

int main(){
  int a[] = {7,9,8,1,-1};

  // The two first parameters are iterators:
  for_each(a, a+5, print_element);  // 7, 9, 8, 1, -1
}