Compilare: user.cpp: In function ‘void Read()’: user.cpp:19:7: warning: unused variable ‘x’ [-Wunused-variable] int i,x; ^ user.cpp: In function ‘void Dfs(int)’: user.cpp:41:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<G[x].size();++i) ^ user.cpp: In function ‘void NrComponents()’: user.cpp:56:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<G[last].size();++j) ^ user.cpp: In function ‘void Read()’: user.cpp:21:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biperm.in","r",stdin); ^ user.cpp:22:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:24:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&A[i].x); ^ user.cpp:27:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&A[i].y); ^ user.cpp: In function ‘void Write()’: user.cpp:70:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biperm.out","w",stdout); ^