🚀 go-pugleaf

  I was working through the Waite Group's C++ Primer (1991), and found
that one of the examples was not working right.  The problem seems to
be that the cin is not returning 0 as expected on invalid input.  I
don't have any real reference book on C++, so I can't be sure things
are supposed to work like this, but my book says (p. 281):

"If, however, the input data does not match cin's expectactions, the
returned value is 0, or false."

  I noticed when the expected data is an int, the expression functions
as expected.

// Check for a cin bug in gcc/2
// Andrew Bros (bros@convex.com)
// September 28, 1992

#include <iostream.h>

int main (void)
{
  double x;
  iostream * rtn;

  cout << "Enter a number (q to quit): ";
  while (rtn = cin >> x) {
    cout << "X = " << x << "\n";
    cout << "Next number (q to quit): ";
  }
  if (rtn == 0) {
    cout << "cin returned " << rtn << "\n";
  }
}

-- 
Andrew Bros                             bros@convex.com
System Integration Group                Convex Computer Corporation
It does not do to leave a live dragon out of your calculations,
if you live near him.  - JRR Tolkien, The Hobbit.