Compilare: user.cpp: In function 'int flux()': user.cpp:80: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int main()': user.cpp:152: warning: comparison between signed and unsigned integer expressions user.cpp:159: warning: comparison between signed and unsigned integer expressions user.cpp:167: warning: comparison between signed and unsigned integer expressions user.cpp:168: warning: comparison between signed and unsigned integer expressions