nibanez80

class RPNCalculator

  def evaluate(expression)
    array = expression.split(' ')

    until array.length == 1
      array.each_with_index do |item, index|
        if item == "+" || item == "*" || item == "-"
          array[index] = eval(array[index - 2] + array[index] + array[index - 1]).to_s

nibanez80

def factorial(n)
  total = 1
  1.upto(n) {|x| total = total * x}
  return total
end

nibanez80

def count_between(array, lower_bound, upper_bound)
  array.find_all {|x| x >= lower_bound && x <= upper_bound}.count
end

nibanez80

class GuessingGame
  attr_accessor :answer, :high, :low, :correct, :guess, :last_guess, :last_result

  def initialize(answer)
    @answer = answer
    @last_result = nil
    @last_guess = nil
    
  end
    

nibanez80

def longest_string(array)
  var = array.sort_by { |x| x.length }

  var.last
end

nibanez80

def mode(array)
  counts = {}
  mode = []
  array.each do |number|
    counts[number] = counts[number].to_i + 1
  end
  largest_count = counts.invert.sort.to_a.last.first
  counts.each_pair do |number, count|
    mode << number if count == largest_count
  end

nibanez80

def median(array)
  med = array.length / 2
  index1 = array[med - 1]
  index2 = array[med]
  odd = (array.length + 1) / 2
  
  if array.length % 2 == 0
    return (index1.to_f + index2.to_f) / 2
  else
    return array[odd - 1]

nibanez80

def mean(array)
  total = array.inject{|sum, x| sum + x}
  total / array.length.to_f
end

nibanez80

def get_grade(array)
  average = (array.inject(:+) / array.size)
  if average >= 90; "A"
  elsif average >= 80; "B"
  elsif average >= 70; "C"
  elsif average >= 60; "D"
  else average >= 50; "F"
  end
end