在一行中初始化一对向量
问题描述：
我想用k对象初始化一个std :: vector（std :: pair）对象，并使用如下所示的一对值。在一行中初始化一对向量
这里是我的尝试：
// int k
std::vector <std::pair<Point::FT, int> >
v(k, (std::numeric_limits<FT>::max(), -1));
错误：
usr/include/c++/4.6/bits/stl_vector.h: In member function ‘void std::vector<T, Allocator>::_M_initialize_dispatch(_Integer, _Integer, std::__true_type) [with _Integer = int, _Tp = std::pair<float, int>, _Alloc = std::allocator<std::pair<float, int> >]’:
/usr/include/c++/4.6/bits/stl_vector.h:340:4: instantiated from ‘std::vector<T, Allocator>::vector(_InputIterator, _InputIterator, const allocator_type&) [with _InputIterator = int, _Tp = std::pair<float, int>, _Alloc = std::allocator<std::pair<float, int> >, std::vector<T, Allocator>::allocator_type = std::allocator<std::pair<float, int> >]’
../Random_kd_tree.h:139:50: instantiated from ‘void Random_kd_tree<DivisionSpace, Tree>::search_nn(std::vector<float>&, int, std::vector<std::pair<float, int> >&) [with DivisionSpace = Division_Euclidean_space, Tree = RKD<Division_Euclidean_space>]’
../main.cpp:51:30: instantiated from here
/usr/include/c++/4.6/bits/stl_vector.h:1080:4: error: no matching function for call to ‘std::vector<std::pair<float, int> >::_M_fill_initialize(std::vector<std::pair<float, int> >::size_type, int&)’
/usr/include/c++/4.6/bits/stl_vector.h:1080:4: note: candidate is:
/usr/include/c++/4.6/bits/stl_vector.h:1122:7: note: void std::vector<T, Allocator>::_M_fill_initialize(std::vector<T, Allocator>::size_type, const value_type&) [with _Tp = std::pair<float, int>, _Alloc = std::allocator<std::pair<float, int> >, std::vector<T, Allocator>::size_type = unsigned int, std::vector<T, Allocator>::value_type = std::pair<float, int>]
/usr/include/c++/4.6/bits/stl_vector.h:1122:7: note: no known conversion for argument 2 from ‘int’ to ‘const value_type& {aka const std::pair<float, int>&}’
答
您可以直接切换到{}在构造周围或参数...
std::vector<std::pair<Point::FT, int>> v{k, {std::numeric_limits<FT>::max(), -1}};
看到它运行here
答
假设Point::FT是后话，这numeric_limits::max()是有效的，
std::vector <std::pair<Point::FT, int>>
v(k, std::make_pair(std::numeric_limits<FT>::max(), -1));
你在一个地方使用'点:: FT'和裸'FT'在另一个 - 你的意思是使用'点:: FT '在std :: numeric_limits'模板中？ – cdhowie 2014-09-10 23:13:51
好点@cdhowie。可能在文件中使用了Point :: FT，但错过了它。 :) – gsamaras 2014-09-10 23:14:25