Compilare: user.cpp: In function ‘int main()’: user.cpp:43: warning: comparison between signed and unsigned integer expressions user.cpp:54: warning: comparison between signed and unsigned integer expressions user.cpp:63: warning: comparison between signed and unsigned integer expressions user.cpp:97: warning: comparison between signed and unsigned integer expressions user.cpp:106: warning: comparison between signed and unsigned integer expressions user.cpp:189: warning: comparison between signed and unsigned integer expressions user.cpp:243: warning: comparison between signed and unsigned integer expressions user.cpp:254: warning: NULL used in arithmetic user.cpp:15: warning: unused variable ‘fc’ user.cpp:16: warning: unused variable ‘cif2’ user.cpp:16: warning: unused variable ‘c’ user.cpp:17: warning: unused variable ‘re’