Compilare: user.cpp: In function ‘void adjacency()’: user.cpp:107:56: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < Adjacency_List[i].size(); j++) { ^ user.cpp: In function ‘void readGraph()’: user.cpp:40:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ user.cpp:42:54: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &num_nodes, &num_arcs, &source); ^ user.cpp:46:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘void write()’: user.cpp:87:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^