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  1. #include <iostream>
  2. #include <string>
  3. #include <map>
  4. #include <functional>
  5.  
  6.  
  7. struct assoc_find_type {
  8.  
  9.    template<typename AssocContainer>
  10.    auto operator ()(AssocContainer & container) const
  11.          -> decltype(std::bind(assoc_find_type{}, std::ref(container), std::placeholders::_1)) {
  12.       return std::bind(assoc_find_type{}, std::ref(container), std::placeholders::_1);      	
  13.    }
  14.  
  15.    template<typename AssocContainer>
  16.    typename AssocContainer::iterator
  17.    operator ()(AssocContainer & container, typename AssocContainer::key_type const& key) const {
  18.       return container.find(key);
  19.    }
  20.  
  21.    template<typename AssocContainer>
  22.    typename AssocContainer::const_iterator
  23.    operator ()(AssocContainer const& container, typename AssocContainer::key_type const& key) const {
  24.       return container.find(key);
  25.    }
  26. };
  27.  
  28. constexpr assoc_find_type assoc_find;
  29.  
  30.  
  31. int main()
  32. {
  33.    using map_t = std::map<std::string, int>;
  34.    map_t map { {"A", 10}, {"B", 11}, {"C", 12}, {"D", 13}, {"E", 14}, {"F", 15} };
  35.  
  36.    auto f = assoc_find(map);
  37.    f("A")->second = 42;
  38.  
  39.    auto u = assoc_find(map);
  40.    std::cout << u("A")->second << std::endl;
  41.  
  42.    return 0;
  43. }
Success #stdin #stdout 0s 3476KB
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Standard input is empty
stdout
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42
https://ideone.com/Y2m0cO
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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