Eroare de compilare: user.c:4:1: error: unknown type name ‘using’ using namespace std; ^ user.c:4:17: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘std’ using namespace std; ^ user.c: In function ‘main’: user.c:9:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sume.in","r",stdin),freopen("sume.out","w",stdout),scanf("%d",&n); ^ user.c:9:38: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sume.in","r",stdin),freopen("sume.out","w",stdout),scanf("%d",&n); ^ user.c:9:67: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("sume.in","r",stdin),freopen("sume.out","w",stdout),scanf("%d",&n); ^ user.c:11:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i]),s+=a[i]; ^