Compilare: user.cpp: In function ‘void DFS1(int)’: user.cpp:61:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < List1[ node ].size(); i++) { ^ user.cpp: In function ‘void DFS2(int)’: user.cpp:74:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < List2[ node ].size(); j++) { ^ user.cpp: In function ‘void displayList()’: user.cpp:136:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < List2[i].size(); j++) { ^ user.cpp: In function ‘void read()’: user.cpp:43:30: 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:45:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &num_nodes, &num_arcs); ^ user.cpp:49:34: 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:85:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^