How to interpret the code “x=numeric(n)”?

Question

I have codes in R, simulate Markov Chain

P = matrix(c(0,1,0,.2,0,.8,.1,.3,.6),nrow=3,byrow=T)
n = 10000
x = numeric(n)
pi0 = c(.5, 0, .5)
state = sample(1:3, 1, p