Compilare: user.cpp:91:2: warning: no newline at end of file user.cpp: In function 'int main()': user.cpp:49: warning: comparison between signed and unsigned integer expressions user.cpp:52: warning: comparison between signed and unsigned integer expressions user.cpp:59: warning: comparison between signed and unsigned integer expressions user.cpp:62: warning: comparison between signed and unsigned integer expressions user.cpp:76: warning: comparison between signed and unsigned integer expressions user.cpp:79: warning: comparison between signed and unsigned integer expressions