CODEWITHSUNDEEP
c++templatesc++11overloading
user2158687
user2158687

Reputation: 55

elegant template overloading solution?

In c++11 I have functions

double f(double x1);
double f(double x1, double x2);
double f(double x1, double x2, double x3);
double h(double x);

I also have functions

double g(std::vector<double> y, double x1);
double g(std::vector<double> y, double x1, double x2);
double g(std::vector<double> y, double x1, double x2, double x3);

The implementation of g is something like

double g(std::vector<double> y, double x1, double x2, double x3)
{
  double ans = 0.0;
  for(g : y)
  {
    ans = h(g) * f(x1, x2, x3);
  }

  return ans;
}

Is there an elegant (templated) way of doing this instead of writing g 3 times with overloaded arguments?

Upvotes: 2

Views: 137

Answers (1)

Yakk - Adam Nevraumont
Yakk - Adam Nevraumont

Reputation: 275878

template<typename... Ts>
double g(std::vector<double> v, Ts&&...ts ) {
  double ret = 1;
  for(auto x:v){
    ret *= h(x)*f(ts...);
  }
  return ret;
}

if you want to restrict the ts to be doubles beyond calling f, it needs more work. Otherwise, the above is enough.

(Note the resriction work gets prettier in C++1y with concepts lite: in C++11 I vote to skip the restriction of Ts to doubles, and just rely on f only taking doubles.)

Upvotes: 10

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