Compilare: main.cpp: In function 'int main()': main.cpp:30:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tractomarm.in","r",stdin); ^ main.cpp:31:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tractomarm.out","w",stdout); ^ main.cpp:32:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &n); ^ main.cpp:34:79: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &nr, &nr1),arbore[nr1].push_back(nr),arbore[nr].push_back(nr1); ^ main.cpp:44:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &m);++m; ^ main.cpp:46:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &nr, &nr1); ^