Compilare: user.cpp: In function ‘void erase(int)’: user.cpp:14:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < h[r].size(); ++i) ^ user.cpp: In function ‘int search(int)’: user.cpp:26:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < h[r].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:38:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hashuri.in","r",stdin); ^ user.cpp:39:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("hashuri.out","w",stdout); ^ user.cpp:43:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&N); ^ user.cpp:46:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&op,&x); ^