foo.cpp: In function 'int main()':
foo.cpp:20:21: error: reference to 'next' is ambiguous
         scanf("%d",&next);
                     ^
foo.cpp:10:13: note: candidates are: int next
 int n,first,next,ans;
             ^
In file included from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_algobase.h:66:0,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/char_traits.h:39,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ios:40,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ostream:38,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/iostream:39,
                 from foo.cpp:1:
C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_iterator_base_funcs.h:184:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^
foo.cpp:21:19: error: reference to 'next' is ambiguous
         if(first<=next) 
                   ^
foo.cpp:10:13: note: candidates are: int next
 int n,first,next,ans;
             ^
In file included from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_algobase.h:66:0,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/char_traits.h:39,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ios:40,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ostream:38,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/iostream:39,
                 from foo.cpp:1:
C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_iterator_base_funcs.h:184:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^
foo.cpp:23:18: error: reference to 'next' is ambiguous
             ans+=next-first;
                  ^
foo.cpp:10:13: note: candidates are: int next
 int n,first,next,ans;
             ^
In file included from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_algobase.h:66:0,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/char_traits.h:39,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ios:40,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ostream:38,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/iostream:39,
                 from foo.cpp:1:
C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_iterator_base_funcs.h:184:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^
foo.cpp:24:21: error: reference to 'next' is ambiguous
             first = next;
                     ^
foo.cpp:10:13: note: candidates are: int next
 int n,first,next,ans;
             ^
In file included from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_algobase.h:66:0,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/char_traits.h:39,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ios:40,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/ostream:38,
                 from C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/iostream:39,
                 from foo.cpp:1:
C:/TDM-GCC-32/lib/gcc/mingw32/4.9.2/include/c++/bits/stl_iterator_base_funcs.h:184:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^
foo.cpp:26:17: error: reference to 'next' is ambiguous
   else if(first>next) 
                 ^
foo.cpp:10:13: note: candidates are: int next
 int n,first,next,ans;
             ^
In file included from C:/TDM-GCC-32/lib/gc