Compilare: user.cpp: In function ‘int main()’: user.cpp:37:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("order.in", "r", stdin); ^ user.cpp:38:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("order.out", "w", stdout); ^ user.cpp:40:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:18:17: warning: ‘sol’ may be used uninitialized in this function [-Wmaybe-uninitialized] X = X - lsb(X); ^ user.cpp:49:23: note: ‘sol’ was declared here int st = 1, dr = N, sol; ^