R Program That Draw Histogram of Coupon's Collector Problem

coupon.R

random.int <- function(n) { sample.int(n, 1) }


random.coupon <- function(...) {
  count <- 0
  have.coupon <- logical(...)
  while (!all(have.coupon)) {
    have.coupon[random.int(...)] <- TRUE
    count <- count + 1
  }
  count
}


sample.coupon <- function(n, size=10*n) {
  result <- NULL
  for (i in 1:size) {
    result <- c(result, random.coupon(n))
  }
  result
}


if (!interactive()) {
  args <- commandArgs(TRUE)
  if (length(args) == 1) {
    filename <- "sample-coupon.png"
  } else if (length(args) == 2) {
    filename <- args[2]
  } else {
    stop("wrong number of argument!")
  }
  png(filename, width=800, height=800)
  arg.list <- list(x=as.numeric(args[1]))
  do.call(hist, list(substitute(sample.coupon(x), arg.list)))
  dev.off()
}