blis.cpp: In function 'int main()': blis.cpp:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result blis.cpp:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result blis.cpp:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result