Compilare: main.c: In function 'main': main.c:27:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen(IFILE, "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:28:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen(OFILE, "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:30:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &p); ^~~~~~~~~~~~~~~