Compilare: user.cpp: In function ‘bool valid(unsigned int, unsigned int)’: user.cpp:7:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= n; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:22:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= n; ++i) ^ user.cpp:16:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tabara.in", "r", stdin); ^ user.cpp:17:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("tabara.out", "w", stdout); ^ user.cpp:20:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:21:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[n + 1]); ^ user.cpp:23:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &v[i]); ^