pack.cpp: In function 'int main()': pack.cpp:57: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result pack.cpp:58: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result pack.cpp:59: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pack.cpp:61: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pack.cpp:62: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result pack.cpp:64: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result