nrbinar.cpp: In function 'int main()': nrbinar.cpp:6: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result nrbinar.cpp:7: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result nrbinar.cpp:9: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result nrbinar.cpp:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result nrbinar.cpp:60: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result nrbinar.cpp:63: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result nrbinar.cpp:69: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result nrbinar.cpp:101: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result nrbinar.cpp:8: warning: 'ok' may be used uninitialized in this function