Compilare: user.cpp: In function ‘int main()’: user.cpp:45: warning: comparison between signed and unsigned integer expressions user.cpp:47: warning: array subscript has type ‘char’ user.cpp:49: warning: array subscript has type ‘char’ user.cpp:57: warning: comparison between signed and unsigned integer expressions user.cpp:59: warning: array subscript has type ‘char’ user.cpp:59: warning: array subscript has type ‘char’