Compilare: user.cpp: In function ‘int main()’: 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 ("sortnet.in", "r", stdin); ^ user.cpp:39:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("sortnet.out", "w", stdout); ^ user.cpp:41:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &N, &M); ^ user.cpp:47:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%c<%d,%d>", &C, &A, &B), A --, B --; ^ user.cpp:20:20: warning: ‘pos’ may be used uninitialized in this function [-Wmaybe-uninitialized] return ((X & (1<<pos)) > 0); ^ user.cpp:54:9: note: ‘pos’ was declared here int pos, val = gray (i) ^ gray (i - 1); ^