ubuntzei.cpp: In function 'int main()': ubuntzei.cpp:53: warning: comparison between signed and unsigned integer expressions ubuntzei.cpp:81: warning: comparison between signed and unsigned integer expressions ubuntzei.cpp:18: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ubuntzei.cpp:19: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ubuntzei.cpp:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ubuntzei.cpp:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ubuntzei.cpp:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result