Compilare: user.cpp: In function ‘int main()’: user.cpp:96:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (n - 1 - list[1].size() <= k) { ^ user.cpp:84:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arborest.out","w",stdout); ^ user.cpp: In constructor ‘Buffer::Buffer(int, std::string)’: user.cpp:20:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(file.c_str(), "r", stdin); ^ user.cpp: In member function ‘void Buffer::reFill()’: user.cpp:45:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(&data[0], 1, dim, stdin); ^