C++ Template MetaProgramming to calculate Square Root

CxxTmp_Sqrt.cxx

template<int N, int i>
struct SqrtM{
	enum{
		ret = (i*i <= N && (i + 1)*(i + 1) > N)?  i : SqrtM<N, i - 1>::ret
	};
};

template<int N>
struct SqrtM<N,0>{
	enum{
		ret = 0
	};
};

template<int N>
struct Sqrt{
	enum{ret = SqrtM<N,N/2>::ret};
};
template<>
struct Sqrt < 1 > {
	enum{ ret = 1 };
};
template<>
struct Sqrt < 0 > {
	enum{ ret = 0 };
};

int main(){
	static_assert(Sqrt<2>::ret==1, "");
	static_assert(Sqrt<3>::ret == 1, "");
	static_assert(Sqrt<4>::ret == 2, "");
	static_assert(Sqrt<9>::ret == 3, "");
	static_assert(Sqrt<10>::ret == 3, "");
	return 0;
}