Compilare: user.c: In function ‘main’: user.c:6:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("numar.in","r",stdin),freopen("numar.out","w",stdout),scanf("%d",&n),x[1]=2,y[1]=n,t=2*n; ^ user.c:6:42: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("numar.in","r",stdin),freopen("numar.out","w",stdout),scanf("%d",&n),x[1]=2,y[1]=n,t=2*n; ^ user.c:6:72: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("numar.in","r",stdin),freopen("numar.out","w",stdout),scanf("%d",&n),x[1]=2,y[1]=n,t=2*n; ^