Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:44:10: warning: unused variable ‘a’ [-Wunused-variable] int i,a=0,b=0; ^ user.cpp:44:14: warning: unused variable ‘b’ [-Wunused-variable] int i,a=0,b=0; ^ user.cpp: In function ‘int main()’: user.cpp:68:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("symmetricgraph2.in","r",stdin); ^ user.cpp:69:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("symmetricgraph2.out","w",stdout); ^ user.cpp:71:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:74:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a,&b,&c); ^