Compilare: user.cpp: In function ‘int main()’: user.cpp:2:105: warning: statement has no effect [-Wunused-value] using namespace std;int s,n,i,j,x;ifstream f("clasic.in");ofstream g("clasic.out");int main(){f>>n;for(i;i<2;i++){f>>n,s=0;for(j=0;j<n;j++){f>>x,s^=x;}g<<s<<'\n';}} ^