sms.cpp: In function 'int main()': sms.cpp:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sms.cpp:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sms.cpp:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sms.cpp:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sms.cpp:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sms.cpp:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result