ubuntzei.cpp: In function 'int main()': ubuntzei.cpp:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ubuntzei.cpp:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ubuntzei.cpp:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ubuntzei.cpp:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ubuntzei.cpp:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result