while.cpp

int main(int argc, char** argv) { return 0; }

#include <iostream>

using namespace std;

template<class Cond, class Expr>
struct While {
  While(Cond& cond, Expr& expr)
  {
    while (cond()) expr();
  }
};

struct CountDown {
  CountDown(long ini)
    : current_(ini)
  {}

  bool operator()()
  {
    return --current_ > 0;
  }

private:
  long current_;
};

struct Hello {
  void operator()()
  {
    std::cout << "hello world." << std::endl;
  }
};

CountDown ten_times(10);
Hello hello;
While<CountDown, Hello> w(ten_times, hello);