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  1. #include <map>
  2. #include <string>
  3.  
  4. struct referent_compare {
  5.     template< typename t >
  6.     bool operator () ( t *lhs, t *rhs )
  7.         { return * lhs < * rhs; }
  8. };
  9.  
  10. template< typename t >
  11. t const *temp_ptr( t const &o ) { return &o; }
  12.  
  13. struct s {
  14.     std::string name;
  15.     long birthdate;
  16.     double score;
  17. };
  18.  
  19. std::map< std::string const *, s, referent_compare > byname;
  20. std::map< double const *, s, referent_compare > byscore;
  21.  
  22. int main() {
  23.     s bob = { "bob", 12000000, 96.3 };
  24.     byname.insert( std::make_pair( & bob.name, bob ) );
  25.     byscore.insert( std::make_pair( & bob.score, bob ) );
  26.  
  27.     byname[ temp_ptr< std::string >( "bob" ) ].score = 33.1;
  28. }
  29.  
Success #stdin #stdout 0.02s 2812KB
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https://ideone.com/GB2jfn
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
public

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