Compilare: user.cpp: In function ‘int main()’: user.cpp:8:15: warning: variable ‘ca’ set but not used [-Wunused-but-set-variable] int a, b, ca, cb, r; ^~ user.cpp:8:19: warning: variable ‘cb’ set but not used [-Wunused-but-set-variable] int a, b, ca, cb, r; ^~ user.cpp:8:23: warning: unused variable ‘r’ [-Wunused-variable] int a, b, ca, cb, r; ^