Compilare: user.cpp:32: warning: non-local variable ‘<anonymous struct> nodes [100000]’ uses anonymous type user.cpp: In function ‘void read_in()’: user.cpp:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result