Place n indistinguishable items into k distinguishable boxes

[Roy Smith]

In article <fq56vu$aue$1 at skeeter.ucdavis.edu>,
 Michael Robertson <mcrobertson at hotmail.com> wrote:

> Hi,
> 
> I need a generator which produces all ways to place n indistinguishable 
> items into k distinguishable boxes.
> 
> For n=4, k=3, there are (4+3-1)!/(3-1)!/4! = 15 ways.
> 
> (0,0,4)
> (0,4,0)
> (4,0,0)
> 
> (0,2,2)
> (2,0,2)
> (2,2,0)
> 
> (0,1,3)
> (0,3,1)
> (3,0,1)
> (3,1,0)
> 
> (1,1,2)
> (1,2,1)
> (2,1,1)
> 
> The generator needs to be fast and efficient.
> 
> Thanks.

What course is this homework problem for?