Calculate Change from a Transaction.

cash register

#Cash Register App by Van Nguyen and Dani Dewitt
require 'date'

puts "What is the amount due?"

amount_due = gets.chomp

puts "What is the amount tendered?"

amount_tendered = gets.chomp

def numeric?(object)
	object =~ /\A\$?\d+(\.\d{1,2})?\z/
end

def has_less_than_three_decimals?(object)
	object.to_s.split(".")[1].length < 3 
end


if numeric?(amount_tendered) && has_less_than_three_decimals?(amount_tendered)
	
	if  amount_tendered.to_f >= amount_due.to_f
		puts "===Thank You!==="
		puts "The total change due is #{sprintf('$%0.2f', (amount_tendered.to_f-amount_due.to_f))}"
		puts ""
		puts DateTime.now
	else
		puts "WARNING: Customer still owes #{sprintf('$%0.2f', (amount_due.to_f-amount_tendered.to_f))}! Exiting..."
	end

else
	puts "WARNING: Invalid currency detected! Exiting..."
end