Compilare: main.c: In function 'main': main.c:7:5: 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; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:7:35: 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; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:7:67: 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; ^~~~~~~~~~~~~~