Compilare: user.cpp: In function ‘void BFS()’: user.cpp:48:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k < vec[i].size(); k++) { ^ user.cpp: In function ‘void DFS(int)’: user.cpp:93:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (z = 0; z < child[x].size(); z++) { ^ user.cpp: In function ‘void ReadTree()’: user.cpp:28:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] } else scanf("%d %d", &i, &j); ^ user.cpp: In function ‘void ProcessOperations()’: user.cpp:150:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &t, &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:171:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disconnect.in", "r", stdin); ^ user.cpp:172:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("disconnect.out", "w", stdout); ^ user.cpp:177:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] } else scanf("%d %d", &N, &M); ^