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In the following snippet of code, I've overloaded the operator== to compare my pair type with string. But for some reason, the compiler isn't finding my operator as a match for the find function. Why not? Edit: Thanks for all the suggestions for alternatives, but I'd still like to understand why . The code looks like it should work; I'd like to know why it doesn't. #include <vector> #include <utility> #include <string> #include <algorithm> typedef std::pair<std::string, int> RegPair; typedef std::vector<RegPair> RegPairSeq; bool operator== (const RegPair& lhs, const std::string& rhs) { return lhs.first == rhs; } int main() { RegPairSeq sequence; std::string foo("foo"); // stuff that's not important std::find(sequence.begin(), sequence.end(), foo); // g++: error: no match for 'operator==' in '__first. __gnu_cxx::__normal_iterator<_Iterator, _Container>::operator* [with _Iterator = std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>*, _Container = std::vector<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int> > >]() == __val' // clang++: error: invalid operands to binary expression ('std::pair<std::basic_string<char>, int>' and 'std::basic_string<char> const') }

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