HW3comp

Ex 13

Please find out all prime numbers from 2 to 100. (Please use “while” to build a “do…until…loop”)

num <- 2:100
i <- 1
obs <- 1
prime <- c()
done <- FALSE

while (!done) {
  n <- num[i]
  factors <- integer(0)  # blank
  
  for (d in 1:n) {
    if (n %% d == 0) {
      factors <- c(factors, d)  # factorize the number first
    }
  }

  if (length(factors) == 2) {
    prime[obs] <- n  # prime number if there's only 2 factors
    obs <- obs + 1
  }

  i <- i + 1
  
  if (i > length(num)) {
    done <- TRUE 
  }
}
prime

##  [1]  2  3  5  7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97