auto.cpp: In function 'void read_and_solve()': auto.cpp:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result auto.cpp:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result auto.cpp: In function 'int main()': auto.cpp:56: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result auto.cpp:57: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result auto.cpp:58: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result