Compilare: user.cpp: In function ‘int main()’: user.cpp:27:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[1].size () && i < v[3].size (); i++) { ^ user.cpp:27:56: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[1].size () && i < v[3].size (); i++) { ^ user.cpp:36:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[2].size (); i++) { ^ user.cpp:45:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = v[1].size () + 1; i < v[3].size (); i+=2) { ^ user.cpp:61:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = v[3].size () + 1; i < v[1].size (); i+=2) { ^ user.cpp:77:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < place[i].size (); j++) ^ 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 ("trenul.in", "rt", stdin); ^ user.cpp:18:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("trenul.out", "wt", stdout); ^