Compilare: user.cpp: In function ‘void write()’: user.cpp:99:21: warning: unknown conversion type character 0xa in format [-Wformat=] printf("%\n"); ^ user.cpp: In function ‘void read()’: user.cpp:17:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &V, &E); ^ user.cpp:20:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &u, &v); ^