Compilare: user.c: In function ‘tipar’: user.c:22:5: warning: format ‘%d’ expects a matching ‘int’ argument [-Wformat=] printf("%d\n"); ^ user.c: In function ‘valid’: user.c:10:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:40:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("permutari.in","r",stdin); ^ user.c:41:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("permutari.out","w",stdout); ^ user.c:42:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c: In function ‘back’: user.c:29:13: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] S[k]=x; ^