Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:75:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < adj[nod].size(); i++) ^ user.cpp: In function ‘void euler(int)’: user.cpp:92:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < adj[nod].size() && ok; i++) ^ user.cpp: In function ‘char get_ch()’: 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(buf_in, 1, buf_size, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:139:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in", "r", stdin); ^ user.cpp:140:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out", "w", stdout); ^