无循环或有条件打印1至1000

编译时间递归！：P

#include <iostream>template<int N>struct NumberGeneration{  static void out(std::ostream& os)  {    NumberGeneration<N-1>::out(os);    os << N << std::endl;  }};template<>struct NumberGeneration<1>{  static void out(std::ostream& os)  {    os << 1 << std::endl;  }};int main(){   NumberGeneration<1000>::out(std::cout);}