ff.cpp: In function 'int main()': ff.cpp:67: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ff.cpp:68: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result ff.cpp:71: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ff.cpp:73: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ff.cpp:74: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result ff.cpp:76: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result