11/17

1.
def diff21(n)
# difference between n and 21
temp = n - 21
# get absolute value of result in 1
new_temp = temp.abs
# if n > 21 then return 2 * result
if n > 21
    return 2 * new_temp
    OR
    ans = 2 * new_temp
end
ans
end

SHORT VERSION
def diff21(n)
    n > 21 ? (21 - n).abs * 2 : (21 - n)
end

2.
def monkey_trouble(a, b)
    # if a and b are true or a and b are false
    # then return true
    # if a is opposite to b
    # then return false
    if (a == true and b == true) || (a == false and b == false) #can also use or instead of ||
        true
    else
        false
    end
end

6.
nums = [1, 2, 7, 1]
def has267(num)
    #contains a 2, 7, 1 pattern
    #comparing an array with another array
    #if array size < 3
    if (nums.size < 3)
        return false
    else
        list = nums*"" # asterisk converts array into string
        if list.include?("271")
            return true
        end

        return false

    end
    #if array contains 2, 7, 1
end

puts has267([1,2,7,1])

class definitions
use ruby car.rb

class Car
    def drive()
        puts "vroom vroom"
    end

    def stop()
        puts "screehh"
    end

    def start()
        puts "rrr"
    end
end

require './car.rb'

c1 = Car.new
c1.start()
c1.drive()
c2 = Car.new