3. Vector aus Pairs mit numerical_limits

Vector aus Pairs mit numerical_limits

  • H

    Hallo,

    ich habe folgenden Code

    #include <vector>
#include <utility>
#include <limits>

using namespace std;

int main(int argc, char **args)
{
  int dim = 4;
  // funktioniert nicht, da will ich hin
  // vector<pair<double, double>> c1(dim,
  //                                 make_pair(numeric_limits<double>::max,
  //                                           numeric_limits<double>::lowest));

  vector<pair<double, double>> c2(dim, make_pair(0.5, 1.5)); // (1) funktioniert

  vector<pair<double, double>> c3(dim, make_pair(numeric_limits<double>::max, 1.5)); // (2) funktioniert nicht

  return 0;
}

    (1) funktioniert mit g++ und clang++ -std=c++11, warum aber nicht (2)? numeric_limits<T>::max gibt T zurück, hier also double. Aus meiner Sicht, sollte (2) damit von den Typen her das gleiche wie (1) sein.

    Danke,

    Florian

    Fehlerausgaben:

    % clang++ --std=c++11 test.cpp
test.cpp:20:32: error: no matching constructor for initialization of 'vector<pair<double, double> >'
  vector<pair<double, double>> c3(dim, make_pair(numeric_limits<double>::max, 1.5)); //funktioniert nicht
                               ^  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:277:7: note: candidate constructor not viable: no known conversion from 'pair<typename __decay_and_strip<double (&)()>::__type, typename
      __decay_and_strip<double>::__type>' to 'const allocator_type' (aka 'const std::allocator<std::pair<double, double> >') for 2nd argument
      vector(size_type __n, const allocator_type& __a = allocator_type())
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:289:7: note: candidate constructor not viable: no known conversion from
      'pair<typename __decay_and_strip<double (&)()>::__type, [...]>' to 'const pair<double, [...]>' for 2nd argument
      vector(size_type __n, const value_type& __value,
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:339:7: note: candidate constructor not viable: no known conversion from 'int' to 'const std::vector<std::pair<double, double>,
      std::allocator<std::pair<double, double> > >' for 1st argument
      vector(const vector& __x, const allocator_type& __a)
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:348:7: note: candidate constructor not viable: no known conversion from 'int' to 'std::vector<std::pair<double, double>,
      std::allocator<std::pair<double, double> > >' for 1st argument
      vector(vector&& __rv, const allocator_type& __m)
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:373:7: note: candidate constructor not viable: no known conversion from 'int' to 'initializer_list<value_type>' for 1st argument
      vector(initializer_list<value_type> __l,
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:401:9: note: candidate template ignored: deduced conflicting types for parameter '_InputIterator'
      ('int' vs. 'std::pair<double (*)(), double>')
        vector(_InputIterator __first, _InputIterator __last,
        ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:264:7: note: candidate constructor not viable: requires single argument '__a', but 2 arguments were provided
      vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:318:7: note: candidate constructor not viable: requires single argument '__x', but 2 arguments were provided
      vector(const vector& __x)
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:335:7: note: candidate constructor not viable: requires single argument '__x', but 2 arguments were provided
      vector(vector&& __x) noexcept
      ^
/usr/bin/../lib64/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../include/c++/4.9.2/bits/stl_vector.h:253:7: note: candidate constructor not viable: requires 0 arguments, but 2 were provided
      vector()
      ^
1 error generated.
    0

  • Da fehlen die Klammern beim Funktionsaufruf von numeric_limits<double>::max() ...

    0
  • H

    Uhh, wie doof von mir... Aus den Fehlermeldungen habe ich es nicht wirklich rauslesen können... Danke Dir!

    0
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