Compilare: user.cpp: In function ‘int main()’: user.cpp:126:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < G[i].size(); j++) ^ user.cpp:97:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("piese3.out", "w", stdout); ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:16:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^