Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:30:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < V[x].size(); ++ i) ^ user.cpp: In function ‘void Dfs(int, int)’: user.cpp:43:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < V[x].size(); ++ i) ^ user.cpp: In function ‘void read()’: user.cpp:14:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("petrica.in", "r", stdin); ^ user.cpp:15:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:18:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] s += v[i]; ^ user.cpp:21:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘void write()’: user.cpp:81:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("petrica.out", "w", stdout); ^