Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:105:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < vertical_intervals.size() && vertical_intervals[i].x < 0) { ^ user.cpp:109:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < vertical_intervals.size() && vertical_intervals[i].x < m-dx) { ^ user.cpp:115:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < vertical_intervals.size() && vertical_intervals[j].x == vertical_intervals[j-1].x); ^ user.cpp:127:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < vertical_intervals.size() && vertical_intervals[i].x == vertical_intervals[i-1].x); ^ In file included from /usr/include/c++/4.8/algorithm:62:0, from user.cpp:2: /usr/include/c++/4.8/bits/stl_algo.h: In instantiation of ‘_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<VerticalInterval*, std::vector<VerticalInterval> >; _Tp = VerticalInterval]’: /usr/include/c++/4.8/bits/stl_algo.h:2307:70: required from ‘_RandomAccessIterator std::__unguarded_partition_pivot(_RandomAccessIterator, _RandomAccessIterator) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<VerticalInterval*, std::vector<VerticalInterval> >]’ /usr/include/c++/4.8/bits/stl_algo.h:2338:54: required from ‘void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<VerticalInterval*, std::vector<VerticalInterval> >; _Size = int]’ /usr/include/c++/4.8/bits/stl_algo.h:5475:36: required from ‘void std::sort(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<VerticalInterval*, std::vector<VerticalInterval> >]’ user.cpp:100:75: required from here /usr/include/c++/4.8/bits/stl_algo.h:2269:19: error: passing ‘const VerticalInterval’ as ‘this’ argument of ‘bool VerticalInterval::operator<(const VerticalInterval&)’ discards qualifiers [-fpermissive] while (__pivot < *__last) ^