Compilare: user.cpp: In function ‘int main()’: user.cpp:40:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < V[C.front()].size(); i += 2){ ^ user.cpp:15:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.in" ,"r", stdin ); ^ user.cpp:16:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bellmanford.out","w", stdout); ^ user.cpp:18:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:22:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &X, &Y, &Z); ^