fig26_22.cpp

C程序设计经典教程第5版程序示例,比较适合初级c语言的学生

// Fig. 26.22: Fig26_22.cpp 
// Testing error states.
#include <iostream>
using std::cin;
using std::cout;
using std::endl;

int main()
{
   int integerValue;

   // display results of cin functions
   cout << "Before a bad input operation:"
      << "\ncin.rdstate(): " << cin.rdstate()
      << "\n    cin.eof(): " << cin.eof()
      << "\n   cin.fail(): " << cin.fail()
      << "\n    cin.bad(): " << cin.bad()
      << "\n   cin.good(): " << cin.good()
      << "\n\nExpects an integer, but enter a character: ";

   cin >> integerValue; // enter character value
   cout << endl;

   // display results of cin functions after bad input
   cout << "After a bad input operation:"
      << "\ncin.rdstate(): " << cin.rdstate()
      << "\n    cin.eof(): " << cin.eof()
      << "\n   cin.fail(): " << cin.fail()
      << "\n    cin.bad(): " << cin.bad()
      << "\n   cin.good(): " << cin.good() << endl << endl;

   cin.clear(); // clear stream

   // display results of cin functions after clearing cin
   cout << "After cin.clear()" << "\ncin.fail(): " << cin.fail()
      << "\ncin.good(): " << cin.good() << endl;
   return 0;
} // end main

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