How to fill in the preceding numbers whenever there is a 0 in R?

Question

I have a string of numbers:

n1 = c(1, 1, 0, 6, 0, 0, 10, 10, 11, 12, 0, 0, 19, 23, 0, 0)

I need to replace 0 with the corresponding number righ

Answer 1

n2 <- n1[cummax(seq_along(n1) * (n1 != 0))]