Compilare: user.cpp: In member function ‘void graph::sort_queries()’: user.cpp:63: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:161: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:162: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:165: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:169: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:178: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result