sir2dif.cpp: In function 'int main()': sir2dif.cpp:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sir2dif.cpp:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result sir2dif.cpp: In function 'void ReadData()': sir2dif.cpp:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sir2dif.cpp:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result sir2dif.cpp:49: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result