Compilare: user.c: In function ‘main’: user.c:5:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("color.in","r",stdin),freopen("color.out","w",stdout),scanf("%lld%lld\n",&n,&m); ^ user.c:5:39: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("color.in","r",stdin),freopen("color.out","w",stdout),scanf("%lld%lld\n",&n,&m); ^ user.c:5:69: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("color.in","r",stdin),freopen("color.out","w",stdout),scanf("%lld%lld\n",&n,&m); ^ user.c:7:7: warning: ignoring return value of ‘gets’, declared with attribute warn_unused_result [-Wunused-result] gets(t); ^ /tmp/ccgATxCk.o: In function `main': user.c:(.text.startup+0xa3): warning: the `gets' function is dangerous and should not be used.