Compilare: user.cpp: In function ‘int main()’: user.cpp:144:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < all_edges.size(); ++ i) ^ user.cpp:151:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < tree.size(); ++ i) ^ user.cpp:169:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < init_tree.size(); ++ j) ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:17:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:39:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^