auto.cpp: In function 'int main()': auto.cpp:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result auto.cpp:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result auto.cpp:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result auto.cpp:43: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result auto.cpp:46: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result