Compilare: user.cpp: In function ‘int main()’: user.cpp:52: warning: operation on ‘i’ may be undefined user.cpp:53: warning: operation on ‘k’ may be undefined user.cpp:54: warning: operation on ‘p’ may be undefined user.cpp:55: warning: operation on ‘j’ may be undefined user.cpp:56: warning: operation on ‘l’ may be undefined user.cpp:57: warning: operation on ‘q’ may be undefined