Compilare: user.cpp: In member function ‘void graph::sort_queries()’: user.cpp:62: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:156: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:157: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:160: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:164: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:171: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result