Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:60:45: warning: statement has no effect [-Wunused-value] eprintf("child of %d, %d\n",u,v); ^ user.cpp: In function ‘int main()’: user.cpp:82:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("clepsidra.in","r",stdin); ^ user.cpp:83:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("clepsidra.out","w",stdout); ^ user.cpp: In function ‘int read()’: user.cpp:41:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] inline int read(){int x;scanf(" %d",&x);return x;} ^