Templates for loop unrolling / metaprogramming.

gistfile1.cpp

#include <iostream>
#include <cstdint>

template<int i, uint64_t val, typename Function>
class Loop {
  public:
    static inline void call(Function f){
      f(i, val);
      Loop<i-1, val, Function>::call(f);
    }
};

template<uint64_t val, typename Function>
class Loop<0, val, Function>{
  public:
    static inline void call(Function f){
      f(0, val);
    }
};

void print(int i, uint64_t val){
  char c = ((val) & (((uint64_t)1) << i)) ? '1' : '0';
  std::cout << c ;
}

int main(void){
  const uint64_t number = 0x00000001;
  Loop<63, number, decltype(print)>::call(print);
  std::cout << std::endl;
  return 0;
}