dans.cpp: In function 'int main()': dans.cpp:23: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result dans.cpp:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result dans.cpp: In function 'void ReadData()': dans.cpp:154: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result dans.cpp:160: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result