c++ - Bad data, try again -

i found code fragment in book:

int ival; // read cin , test eof; loop executed if there other io failures while (cin >> ival, !cin.eof()) {     if (cin.bad())         // input stream corrupted; bail out         throw runtime_error("io stream corrupted");     if (cin.fail()) {                        // bad input         cerr<< "bad data, try again";        // warn user         cin.clear(istream::failbit);         // reset stream         istream::iostate cin_state = cin.rdstate();         continue;                            // next input     }     // ok process ival } 

if click 'f' in command window, countless "bad data, try again", , cin_state 0x02, equal badbit. failbit has not been clear, why?

the issue f never removed input stream, cin >> ival keeps trying read on , on again.

you need skip past it. see, example, how istream::ignore( ) work?