解决微软面试题

// grammer.cpp : 定义控制台应用程序的入口点。//made by davidsu33//第12题（语法）微软面试题//题目：求1+2+…+n，//要求不能使用乘除法、for、while、if、else、switch、case等关键字以及条件判断语句（A?B:C）。#include "stdafx.h"#include <iostream>#include <vector>#include <cassert>using namespace std;template<unsigned int>struct acclum;template<>struct acclum<0>{enum {value = 0,};};template<>struct acclum<1>{enum {value = 1,};};template<unsigned int N>struct acclum{enum{ value = (N + acclum<N-1>::value),};};int _tmain(int argc, _TCHAR* argv[]){int sum = 0;for (unsigned i=1; i<=100; ++i){sum += i;}assert(acclum<100>::value == sum);assert(acclum<0>::value == 0);return 0;}