Project Euler . Problem 7 . 10001st prime : By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13. What is the 10 001st prime number?

projecteuler7.rb

$TARGETNUM = 10001
$primeNum = []
$i = 1
$cnt = 0
loop do
  flag = true
  x = 2
  while x<$i 
    # p x
    if $i % x==0 then
      flag = false
      break
    end
    x += 1
  end
  if flag then
    $primeNum.push($i)
    p "[#{$cnt.to_i}] : #{$i.to_i}" if $cnt>0
    break if $cnt == $TARGETNUM
    $cnt += 1
  end
  $i += 1
end