reactii.cpp: In function 'int main()': reactii.cpp:16: error: '>>' should be '> >' within a nested template argument list reactii.cpp:24: error: no matching function for call to 'std::stack<std::pair<int, int>, std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > > >::push(int&, int&)' /usr/include/c++/4.4/bits/stl_stack.h:182: note: candidates are: void std::stack<_Tp, _Sequence>::push(const typename _Sequence::value_type&) [with _Tp = std::pair<int, int>, _Sequence = std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > >] reactii.cpp:28: error: 'a' was not declared in this scope reactii.cpp:28: error: 'b' was not declared in this scope reactii.cpp:35: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x reactii.cpp:35: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x reactii.cpp:27: warning: unused variable 'ok'