Eroare de compilare: user.cpp: In function ‘void back(char, char, char)’: user.cpp:21: warning: array subscript has type ‘char’ user.cpp:41: warning: array subscript has type ‘char’ user.cpp:41: warning: array subscript has type ‘char’ user.cpp:41: error: no match for ‘operator=’ in ‘it = vec[((int)i)][((int)j)].std::vector<_Tp, _Alloc>::begin [with _Tp = std::pair<char, char>, _Alloc = std::allocator<std::pair<char, char> >]()’ /usr/include/c++/4.4/bits/stl_iterator.h:669: note: candidates are: __gnu_cxx::__normal_iterator<std::pair<int, int>*, std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > > >& __gnu_cxx::__normal_iterator<std::pair<int, int>*, std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > > >::operator=(const __gnu_cxx::__normal_iterator<std::pair<int, int>*, std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > > >&) user.cpp:41: warning: array subscript has type ‘char’ user.cpp:41: warning: array subscript has type ‘char’ user.cpp:41: error: no match for ‘operator!=’ in ‘it != vec[((int)i)][((int)j)].std::vector<_Tp, _Alloc>::end [with _Tp = std::pair<char, char>, _Alloc = std::allocator<std::pair<char, char> >]()’ user.cpp:46: warning: array subscript has type ‘char’ user.cpp: In function ‘int main()’: user.cpp:73: warning: comparison between signed and unsigned integer expressions user.cpp:93: warning: array subscript has type ‘char’ user.cpp:93: warning: array subscript has type ‘char’ user.cpp:106: warning: array subscript has type ‘char’ user.cpp:106: warning: array subscript has type ‘char’ user.cpp:107: warning: array subscript has type ‘char’ user.cpp:107: warning: array subscript has type ‘char’ user.cpp:112: warning: comparison between signed and unsigned integer expressions user.cpp:55: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:56: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:59: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:63: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result