sub.cpp: In function 'int main()': sub.cpp:81: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sub.cpp:82: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sub.cpp:83: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sub.cpp:86: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sub.cpp:89: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sub.cpp:95: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sub.cpp:101: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result