[問題] 關於 template instantiation 的問題

看板C_and_CPP作者zhouer (　)時間15年前 (2010/11/24 00:35)推噓7(7推 0噓 14→)

留言21則, 7人參與討論串1/1

下面這兩行是正確的： vector<int> v; remove_if(v.begin(), v.end(), bind1st(less<int>(), 0)); 如果把 less<int> 換成 less<const int> 或是 less<const int&> 都會 compile error 但如果是像下面這麼寫： vector<int>::iterator iter = v.begin(); less<const int&>()(*iter, 0); less<> 中的東西不論是 <int>, <const int>, <const int&> 都可以正常 compile，請問這是什麼原因呢？錯誤訊息如下： In file included from /usr/include/c++/4.4/bits/stl_function.h:712, from /usr/include/c++/4.4/functional:50, from vec.cc:2: /usr/include/c++/4.4/backward/binders.h: In instantiation of ‘ std::binder1st<std::less<const int&> >’: vec.cc:11: instantiated from here /usr/include/c++/4.4/backward/binders.h:117: error: ‘typename _Operation::result_type std::binder1st<_Operation>::operator()(typename _Operation::second_argument_type&) const [with _Operation = std::less<const int&>]’ cannot be overloaded /usr/include/c++/4.4/backward/binders.h:111: error: with ‘typename _Operation::result_type std::binder1st<_Operation>::operator()(const typename _Operation::second_argument_type&) const [with _Operation = std::less<const int&>]’ -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 139.175.68.252

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