Compilare: user.cpp: In function ‘int main()’: user.cpp:13: warning: comparison between signed and unsigned integer expressions user.cpp:14: warning: comparison between signed and unsigned integer expressions user.cpp:22: warning: comparison between signed and unsigned integer expressions user.cpp:23: warning: comparison between signed and unsigned integer expressions user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:29: warning: comparison between signed and unsigned integer expressions user.cpp:30: warning: comparison between signed and unsigned integer expressions user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp:35: warning: comparison between signed and unsigned integer expressions user.cpp:38: warning: comparison between signed and unsigned integer expressions user.cpp:40: warning: comparison between signed and unsigned integer expressions