Compilare: user.cpp: In function ‘int main()’: user.cpp:9:9: warning: unused variable ‘a’ [-Wunused-variable] int a,b; ^ user.cpp:9:11: warning: unused variable ‘b’ [-Wunused-variable] int a,b; ^ user.cpp:18:14: warning: variable ‘sf’ set but not used [-Wunused-but-set-variable] int sf=0; ^