cofetar.cpp: In function 'void read()': cofetar.cpp:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result cofetar.cpp:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cofetar.cpp:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cofetar.cpp:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cofetar.cpp:37: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cofetar.cpp:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cofetar.cpp:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result cofetar.cpp: In function 'void write()': cofetar.cpp:109: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result