Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:23:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ user.cpp: In function ‘int main()’: user.cpp:31:10: warning: unused variable ‘cin’ [-Wunused-variable] FILE*cin=freopen("dfs.in","r",stdin); ^ user.cpp:32:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:34:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^