Compilare: main.c: In function 'main': main.c:8:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen(FIN,"r",stdin); ^~~~~~~~~~~~~~~~~~~~~~ main.c:9:3: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT,"w",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~ main.c:10:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a); ^~~~~~~~~~~~~~~ main.c:11:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &b); ^~~~~~~~~~~~~~~