Compilare: user.c: In function ‘main’: user.c:64:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("compresie.in", "r", stdin); ^ user.c:65:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("compresie.out", "w", stdout); ^ user.c:67:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", str_in); ^ user.c:99:27: warning: ‘j’ may be used uninitialized in this function [-Wmaybe-uninitialized] buf[j]=str_in[i]; ^