6. State Check Example

• 
  #include <iostream>
  using std::cin;
  using std::cout;
  int main()
  {
      cout << "Please type some numbers separated by spaces or semicolons.\n";
      cout << "Type CTRL+Z followed by ENTER on windows (or CTRL+D on unix) to exit.\n";
      for (;;) {
          int value = 0;
          if ( !( cin >> value ) ) {
              // cin is not good, more checks required.
              // NOTE: the value is likely to contain garbage!
              if ( cin.bad() ) {
                  cout << "cin is corrupted, exiting the program.\n";
                  return 1; // signal error back to the operating system
              }
              if ( cin.eof() ) {
                  cout << "EOF found, exiting the program.\n";
                  return 0; // signal success to the operating system
              }
              if ( cin.fail() ) {
                  cin.clear(); // go back to good state.
                  // do something to recover...
                  char ch = 0;
                  if ( cin >> ch ) {
                      if ( ch == ';' ) {
                          // semicolon is data delimiter, and can be ignored:
                          continue;
                      }
                      cout << "Sorry, character [" << ch << "] was unexpected at this time. Exiting...\n";
                      break;
                  }
              }
          }
          cout << "You entered: " << value << '\n';
      }//for
      return 0;
  }