模板元编程

#include <iostream>
2 using namespace std;
3 template<int n>struct factoria{
4 enum{ val = factoria<n-1>::val * n};//注意n后面没有;只有union abc{int a;double b;};
5 };
6 template<>struct factoria<0>{
7 enum{val = 1};
8 };
9 void f1(){
10 for(int i =1;i < 10;i ++){
11 cout << factoria<5>::val << endl;//不能用i来代替5
12 }
13 }
14 int main(){
15
16 f1();
17
18 return 0;
19 }

 

template<int n>struct fab{
18 enum{ val = fab<n-1>::val + fab<n-2>::val};
19 };
20 template<>struct fab<0>{
21 enum{val = 1};
22 };
23 template<>struct fab<1>{
24 enum{val =1};
25 };
26 void f2(){
27 cout << fab<1>::val << endl;
28 cout << fab<2>::val << endl;
29 cout << fab<3>::val << endl;
30 cout << fab<4>::val << endl;
31 cout << fab<5>::val << endl;
32 cout << fab<6>::val << endl;
33 cout << fab<7>::val << endl;
34 cout << fab<8>::val << endl;

}