Compilare: user.cpp: In function 'void back(char, std::vector<std::pair<char, char>, std::allocator<std::pair<char, char> > >)': user.cpp:30: warning: array subscript has type 'char' user.cpp:34: warning: array subscript has type 'char' user.cpp:34: warning: array subscript has type 'char' user.cpp:34: warning: array subscript has type 'char' user.cpp:35: warning: array subscript has type 'char' user.cpp:46: warning: array subscript has type 'char' user.cpp:46: warning: array subscript has type 'char' user.cpp:46: warning: array subscript has type 'char' user.cpp:47: warning: array subscript has type 'char' user.cpp:51: warning: array subscript has type 'char' user.cpp:55: warning: array subscript has type 'char' user.cpp:55: warning: array subscript has type 'char' user.cpp:55: warning: array subscript has type 'char' user.cpp:56: warning: array subscript has type 'char' user.cpp:67: warning: array subscript has type 'char' user.cpp:67: warning: array subscript has type 'char' user.cpp:67: warning: array subscript has type 'char' user.cpp:68: warning: array subscript has type 'char' user.cpp:72: warning: array subscript has type 'char' user.cpp:76: warning: array subscript has type 'char' user.cpp:76: warning: array subscript has type 'char' user.cpp:76: warning: array subscript has type 'char' user.cpp:77: warning: array subscript has type 'char' user.cpp:88: warning: array subscript has type 'char' user.cpp:88: warning: array subscript has type 'char' user.cpp:88: warning: array subscript has type 'char' user.cpp:89: warning: array subscript has type 'char' user.cpp:93: warning: array subscript has type 'char' user.cpp:97: warning: array subscript has type 'char' user.cpp:97: warning: array subscript has type 'char' user.cpp:97: warning: array subscript has type 'char' user.cpp:98: warning: array subscript has type 'char' user.cpp:109: warning: array subscript has type 'char' user.cpp:109: warning: array subscript has type 'char' user.cpp:109: warning: array subscript has type 'char' user.cpp:110: warning: array subscript has type 'char'