fork(2) download 
  1. #include <functional>
  2.  
  3. template<class Callable1, class Callable2>
  4. struct Chain : public std::unary_function<
  5.     typename Callable2::argument_type, 
  6.     typename Callable1::result_type>
  7. {
  8.     Chain(const Callable1 &f1, const Callable2 &f2) : f1(f1), f2(f2) {}
  9.  
  10.     typename Callable1::result_type operator () (typename Callable2::argument_type param) { return f1(f2(param)); }
  11. private:
  12.     Callable1 f1;
  13.     Callable2 f2;
  14. };
  15.  
  16. template<class Callable1, class Callable2>
  17. Chain<Callable1, Callable2> chain(const Callable1 &f1, const Callable2 &f2) {
  18.     return Chain<Callable1, Callable2>(f1, f2);
  19. }
  20.  
  21. #include <string>
  22. #include <iostream>
  23. #include <sstream>
  24.  
  25. using namespace std;
  26.  
  27. struct foo : public unary_function<int, double> {
  28.     double m;
  29.     foo(double m) : m(m) {}
  30.     double operator() (int x) { return m + x; }
  31. };
  32.  
  33. struct bar : public unary_function<double, string> {
  34.     string operator() (double y) {
  35.         stringstream ss;
  36.         ss << y;
  37.         return ss.str();
  38.     }
  39. };
  40.  
  41. int main() {
  42.     cout << foo(0.4)(5) << endl;
  43.     cout << bar()(4.5) << endl;
  44.  
  45.     cout << chain(bar(), foo(3.4))(7) << endl;
  46. }
  47.  
Success #stdin #stdout 0s 3472KB
comments ()
stdin 
Standard input is empty
stdout 
5.4
4.5
10.4
https://ideone.com/7QpmEU
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!