C++14 style

main.cpp

#include <vector>
#include <functional>
#include <memory>
#include <iostream>

using namespace std;

class Unit
{
public:
  int health;
};

using UnitPtr=shared_ptr<Unit>;

class Trap
{
public:
  Trap(int p):power(p)
  {
    cout << "trap maked with power " << p << endl;
  }
  int power = 0;
};


void activate(Trap const& t, UnitPtr const& target)
{
  target->health -= t.power;
}

int main(int argc, char *argv[])
{
  // only one Trap initialization

  auto forestTrapIt = bind(activate, Trap{10}, placeholders::_1);

  // lambda capture move
  auto mountainTrapIt = [trap=Trap{20}](auto t) { activate(trap, t); };

  // like simple definition of function, but in runtime
  auto waterTrapIt = [](auto t)
  {
    static const Trap trap{30};
    activate(trap, t);
  };

  UnitPtr h { new Unit{100} };

  forestTrapIt(h);
  forestTrapIt(h);

  mountainTrapIt(h);
  mountainTrapIt(h);

  waterTrapIt(h);
  waterTrapIt(h);

  cout << h->health << endl;

  return 0;
}