Compilare: user.cpp: In function ‘int main()’: user.cpp:109:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harbingers.in","r",stdin); ^ user.cpp:110:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harbingers.out","w",stdout); ^ user.cpp:112:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:118:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a,&b,&c); ^ user.cpp:125:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&intra[i],&viteza[i]); ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:73:17: warning: ‘a’ is used uninitialized in this function [-Wuninitialized] stv[rez].a=a; ^ user.cpp:74:17: warning: ‘b’ is used uninitialized in this function [-Wuninitialized] stv[rez].b=b; ^