How To Clear an istream Object During Extraction

MORE INFORMATION

Sample Code

   /* No special compile options needed. */ 

  #include <iostream.h>

   int ClearError(istream& isIn)        // Clears istream object
   {
      streambuf*  sbpThis;
      char        szTempBuf[20];
      int         nCount, nRet = isIn.rdstate();

      if  (nRet)                        // Any errors?
      {
          isIn.clear();                 // Clear error flags
          sbpThis = isIn.rdbuf();       // Get streambuf pointer
          nCount = sbpThis->in_avail(); // Number of characters in buffer

          while (nCount)                // Extract them to szTempBuf
          {
              if  (nCount > 20)
              {
                  sbpThis->sgetn(szTempBuf, 20);
                  nCount -= 20;
              }
              else
              {
                  sbpThis->sgetn(szTempBuf, nCount);
                  nCount = 0;
              }
          }
      }

      return  nRet;
   }

   void main()
   {
      int  n = 0, nState;
      while (n <= 100)
      {
         cout << "Please enter an integer greater than 100.\n";
         cin >> n;
         nState = ClearError(cin);   // Clears any errors in cin
      }
   }