1template <int n> class vec { 2 double x[n]; 3 4 public: 5 vec() { 6 for (int i=0; i<n-1; ++i) x[i]=0; 7 } 8 9 vec(const vec<n>& v) { 10 for (int i=0; i<n; ++i) x[i]=v(i); 11 } 12 13 vec(const vec<n-1>& v, const double& y) { 14 for (int i=0; i<n-1; ++i) x[i]=v(i); 15 x[n-1]=y; 16 } 17 18 inline double operator()(const int i) const { 19 return x[i]; 20 } 21}; 22 23 24template <int n> vec<n + 1>& operator,(const vec<n>& v, const double& y) { 25 return *(new vec<n + 1>(v, y)); 26} 27 28 29int main() { 30 vec<4> v; 31 vec<5> w; 32 w=(v,3.); 33} 34