Compilare: user.cpp: In function ‘int main()’: user.cpp:209:9: warning: unused variable ‘i’ [-Wunused-variable] int i , rv , n , k , e; ^ user.cpp:209:13: warning: unused variable ‘rv’ [-Wunused-variable] int i , rv , n , k , e; ^~ user.cpp:209:18: warning: unused variable ‘n’ [-Wunused-variable] int i , rv , n , k , e; ^ user.cpp:209:22: warning: unused variable ‘k’ [-Wunused-variable] int i , rv , n , k , e; ^ user.cpp:209:26: warning: unused variable ‘e’ [-Wunused-variable] int i , rv , n , k , e; ^ user.cpp:210:10: warning: unused variable ‘ch’ [-Wunused-variable] char ch; ^~