Compilare: user.cpp: In function 'int eval(char*, int, int*)': user.cpp:56: warning: operation on 'vf' may be undefined user.cpp:56: warning: operation on 'vf' may be undefined user.cpp:57: warning: operation on 'vf' may be undefined user.cpp:57: warning: operation on 'vf' may be undefined user.cpp:58: warning: operation on 'vf' may be undefined user.cpp:58: warning: operation on 'vf' may be undefined