Compilare: user.cpp: In function ‘int main()’: user.cpp:2:97: warning: right operand of comma operator has no effect [-Wunused-value] using namespace std;int a,n,s;int main(){ifstream f("clasic.in");ofstream g("clasic.out");f>>n,n;for(s=0;n;){for(;n;--n)f>>a,s^=a;g<<s<<'\n',f>>n;}} ^