Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:16:19: warning: variable ‘nod’ set but not used [-Wunused-but-set-variable] int nrnod=0 , nod; ^ user.cpp: In function ‘int main()’: user.cpp:62:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("itree.in","r",stdin); ^ user.cpp:63:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("itree.out","w",stdout); ^ user.cpp:65:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^ user.cpp:68:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:73:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ",&x,&y ); ^