spp.cpp: In function 'int main()': spp.cpp:44: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x spp.cpp:44: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x spp.cpp:51: error: expected initializer before ':' token spp.cpp:59: error: expected primary-expression at end of input spp.cpp:59: error: expected ';' at end of input spp.cpp:59: error: expected primary-expression at end of input spp.cpp:59: error: expected ')' at end of input spp.cpp:59: error: expected statement at end of input spp.cpp:50: warning: unused variable 'ret' spp.cpp:59: error: expected '}' at end of input In file included from /usr/include/c++/4.4/algorithm:62, from /usr/include/c++/4.4/i486-linux-gnu/bits/stdc++.h:63, from spp.cpp:1: /usr/include/c++/4.4/bits/stl_algo.h: In function 'const _Tp& std::__median(const _Tp&, const _Tp&, const _Tp&) [with _Tp = Edge]': /usr/include/c++/4.4/bits/stl_algo.h:2268: instantiated from 'void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<Edge*, std::vector<Edge, std::allocator<Edge> > >, _Size = int]' /usr/include/c++/4.4/bits/stl_algo.h:5220: instantiated from 'void std::sort(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<Edge*, std::vector<Edge, std::allocator<Edge> > >]' spp.cpp:46: instantiated from here /usr/include/c++/4.4/bits/stl_algo.h:89: error: passing 'const Edge' as 'this' argument of 'bool Edge::operator<(const Edge&)' discards qualifiers /usr/include/c++/4.4/bits/stl_algo.h:90: error: passing 'const Edge' as 'this' argument of 'bool Edge::operator<(const Edge&)' discards qualifiers /usr/include/c++/4.4/bits/stl_algo.h:92: error: passing 'const Edge' as 'this' argument of 'bool Edge::operator<(const Edge&)' discards qualifiers /usr/include/c++/4.4/bits/stl_algo.h:96: error: passing 'const Edge' as 'this' argument of 'bool Edge::operator<(const Edge&)' discards qualifiers /usr/include/c++/4.4/bits/stl_algo.h:98: error: passing 'const Edge' as 'this' argument of 'bool Edge::operator<(const Edge&)' discards qualifiers