Recursive function using dplyr

Question

I have data:

dat <- tibble(
         day = 200:210,
         x = sample(-10:10, size = 11,replace = T))

I have a variable y

Answer 1

df %>% mutate(y = 5 + cumsum(x))

or, with your extra conditions

df %>% mutate(y = (5 + cumsum(x)) %>% pmin(10) %>% pmax(0))