Compilare: user.cpp: In function ‘void del(int, int)’: user.cpp:51:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[from].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:88:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < G[u].size(); i++) { ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:14:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,SIZE,1,input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:39:46: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff,SIZE,1,input_file); ^