# A silly little test program that finds prime numbers.  It
# is intentionally badly designed to show off the use
# or ruby-prof.
# 
# Source from http://people.cs.uchicago.edu/~bomb154/154/maclabs/profilers-lab/

def make_random_array(length, maxnum)
	result = Array.new(length)
	result.each_index do |i|
		result[i] = rand(maxnum)
	end
		
	result
end
 
def is_prime(x)
	y = 2
	y.upto(x-1) do |i|
		return false if (x % i) == 0
	end
	true
end

def find_primes(arr)
	result = arr.select do |value|
		is_prime(value)
	end
	result
end

def find_largest(primes)
	largest = primes.first

	# Intentionally use upto for example purposes
	# (upto is also called from is_prime)
	0.upto(primes.length-1) do |i|
    sleep(0.02)
    prime = primes[i]
		if prime > largest
			largest = prime
		end
	end
	largest
end

def run_primes
	length = 500	
  maxnum = 10000
  
  # Create random numbers
 	random_array = make_random_array(length, maxnum)
 	
 	# Find the primes
  primes = find_primes(random_array)
  
  # Find the largest primes
 	largest = find_largest(primes)
end