Compilare: main.c: In function 'main': main.c:5:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("reactivi.in","r",stdin),freopen("reactivi.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:38: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("reactivi.in","r",stdin),freopen("reactivi.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:73: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] freopen("reactivi.in","r",stdin),freopen("reactivi.out","w",stdout),scanf("%d",&n); ^~~~~~~~~~~~~~ main.c:7:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",a+i,b+i); ^~~~~~~~~~~~~~~~~~~~~