Compilare: user.cpp: In function ‘int main()’: user.cpp:38:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < x.size(); ++ i) { ^ user.cpp:52:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < x.size(); ++ i) ^ user.cpp:53:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(x[i] == normal.size() - 1 && d[i] != -1) ^ user.cpp:56:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(res == x.size() + 1) ^ user.cpp:17:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv.in", "r", stdin); ^ user.cpp:18:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("secv.out", "w", stdout); ^ user.cpp:21:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:27:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &val); ^