Compilare: user.cpp: In function ‘int main()’: user.cpp:8:6: warning: unused variable ‘x’ [-Wunused-variable] {int x,y,a,b,i,n,sum=0; ^ user.cpp:8:8: warning: unused variable ‘y’ [-Wunused-variable] {int x,y,a,b,i,n,sum=0; ^ user.cpp:8:10: warning: unused variable ‘a’ [-Wunused-variable] {int x,y,a,b,i,n,sum=0; ^ user.cpp:8:12: warning: unused variable ‘b’ [-Wunused-variable] {int x,y,a,b,i,n,sum=0; ^