Linq statement for an infinite sequence of successive halves

Question

Given a starting number, imagine an infinite sequence of its successive halves.

1, 0.5, 0.25, 0.125, ...

(Ignore any numerical instabilities inherent in double.)

Can this be done in a single expression without writing any custom extension methods or generator methods?

Answer 1

I don't know of a single-expression way but I found this clever generator code here: http://csharpindepth.com/articles/Chapter11/StreamingAndIterators.aspx

public static IEnumerable<TSource> Generate<TSource>(TSource start,
                                                  Func<TSource,TSource> step)
{
   TSource current = start;
   while (true)
   {
       yield return current;
       current = step(current);
   }
}

In your case you'd use it:

foreach (double d in Generate<double>(1, c => c / 2))
{
    ...
}