fork download 
  1. #include <utility>
  2.  
  3. struct my_complex
  4. {
  5.         float r, i;
  6.  
  7.         my_complex(float r, float i)
  8.                 : r(r), i(i)
  9.         {}
  10.  
  11.         template <typename Expr>
  12.         my_complex(Expr expr)
  13.         {
  14.                 auto result = expr();
  15.                 r = result.r;
  16.                 i = result.i;
  17.         }
  18. };
  19.  
  20. struct addition
  21. {
  22.         my_complex const& lhs;
  23.         my_complex const& rhs;
  24.  
  25.         addition(my_complex const& lhs, my_complex const& rhs)
  26.                 : lhs(lhs), rhs(rhs)
  27.         {}
  28.  
  29.         my_complex operator () ()
  30.         {
  31.                 return my_complex(lhs.r + rhs.r, lhs.i + rhs.i);
  32.         }
  33. };
  34.  
  35. addition operator + (my_complex const& lhs, my_complex const& rhs)
  36. {
  37.         return addition(lhs, rhs);
  38. }
  39.  
  40. int main()
  41. {
  42.         my_complex a(42.f, 666.f);
  43.         my_complex b(3.14f, 2.7f);
  44.  
  45.         auto c = a + b;
  46.  
  47.         std::swap(a, c);
  48. }
Compilation error #stdin compilation error #stdout 0s 0KB
comments ()
stdin 
Standard input is empty
compilation info 
prog.cpp: In function 'int main()':
prog.cpp:47:23: error: no matching function for call to 'swap(my_complex&, addition&)'
stdout 
Standard output is empty
https://ideone.com/qHcHL
language:
C++14 (gcc 8.3)
created:
13 years ago
visibility:
public

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!