Eroare de compilare: In file included from /usr/include/c++/4.8/algorithm:62:0, from /usr/include/i386-linux-gnu/c++/4.8/bits/stdc++.h:64, from user.cpp:1: /usr/include/c++/4.8/bits/stl_algo.h: In instantiation of ‘_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&) [with _RandomAccessIterator = interval*; _Tp = interval]’: /usr/include/c++/4.8/bits/stl_algo.h:2307:70: required from ‘_RandomAccessIterator std::__unguarded_partition_pivot(_RandomAccessIterator, _RandomAccessIterator) [with _RandomAccessIterator = interval*]’ /usr/include/c++/4.8/bits/stl_algo.h:2338:54: required from ‘void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size) [with _RandomAccessIterator = interval*; _Size = int]’ /usr/include/c++/4.8/bits/stl_algo.h:5475:36: required from ‘void std::sort(_RAIter, _RAIter) [with _RAIter = interval*]’ user.cpp:55:23: required from here /usr/include/c++/4.8/bits/stl_algo.h:2269:19: error: passing ‘const interval’ as ‘this’ argument of ‘bool interval::operator<(const interval&)’ discards qualifiers [-fpermissive] while (__pivot < *__last) ^