Compilare: user.cpp: In function 'void attach(int)': user.cpp:16: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void prelucrare()': user.cpp:47: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void attach(int)': user.cpp:13: warning: 'nr' may be used uninitialized in this function