Compilare: user.cpp: In function ‘void df(int, int)’: user.cpp:38:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<v[nod].size(); ++i) ^ user.cpp: In function ‘void unlockGroup(int)’: user.cpp:52:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<w[pz].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:156:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<v[nod].size(); ++j) ^ user.cpp:70:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortop.in", "r", stdin); ^ user.cpp:71:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortop.out", "w", stdout); ^ user.cpp:73:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:81:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ user.cpp:92:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ user.cpp:104:25: warning: ‘poz’ may be used uninitialized in this function [-Wmaybe-uninitialized] unlockGroup(val[poz]); ^