Generating combinations with repetitions

[Tomaz Ficko]

Can someone post code for generating all combinations of k elements out of n
elements with repetitions.

Example:
elements = 1,2,3,4  and k=3

111, 112, 113, 114,
222, 221, 223, 224,
333, 331, 332, 334,
444, 441, 442, 443,
123, 124, 134, 234

Thanks.

Tomaz