unudoi.cpp: In function 'int main()': unudoi.cpp:45: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result unudoi.cpp:46: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result unudoi.cpp:47: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result unudoi.cpp:48: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result unudoi.cpp:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result