On pp. 150 in chapter 3 - the book states (In the section - "Floating Point Loop Counters", in the middle of the second paragraph where the author tries to provide an example of a for loop which would never terminate):

"This means that you should not code a for loop such that ending the loop depends on a floating-point loop counter reaching a precise value. For example, the following pporly-designed loop never ends.

for (double x = 0.0 ; x!= 1.0 ; x+= 0.2)
cout <<x;

I tried it but the loop actually ends.
I got the following output: 00.20.40.60.8.

Then I added an endl to get slightly better output and I got:
0
0.2
0.4
0.6
0.8
--
Here is my code:

#include <iostream>

using std::cout;
using std::endl;

int main()
{
for (double x = 0.0; x != 1.0; x += 0.2)
cout << x << endl;
return 0;
}
----

I have submitted this to the book team as well. Any comments on this? Has anyone tried it out? I am essentially not able to substatiate the authors claim that the loop would continue forever. Thanks much.

I can also confirm that the problem the original poster describes is the same for me. It is difficult to understand what the authors intention was with this example.

Of course, if I increment by 0.3 instead of 0.2 then the loop never ends, but I would be surprised if this was the authors intention. Maybe there is an errata for this.