roci.cpp: In function 'int main()': roci.cpp:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result roci.cpp:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result roci.cpp:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result roci.cpp:13: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result roci.cpp:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result