1 template<typename T_D, typename T_U> 2 T_D pow(T_D a, T_U b){ 3     T_D ans = 1, base = a; 4     while(b){ 5         if(b % 2 == 1){ 6             ans *= base; 7         } 8         base *= base; 9         b /= 2;10     }11     return ans;    12 }13 14 int main(){15     long long a = 8;16     cout << pow(a, 10);17 }