Compilare: user.c: In function ‘main’: user.c:7:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("texttrim.in","r",stdin); ^ user.c:8:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("texttrim.out","w",stdout); ^ user.c:10:20: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] fr(i,0,27)scanf("%i",a+i); ^ user.c:11:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ user.c:12:9: warning: ignoring return value of ‘gets’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.c:14:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i",&b); ^ /tmp/ccNFY1BK.o: In function `main': user.c:(.text.startup+0x89): warning: the `gets' function is dangerous and should not be used.