Cashier Problem 2

gistfile1.txt

def error_message
  puts "Error invalid amount of money exiting program"
end

def number_check(number)
    number =~ /^\d+(\.\d{0,2})?$/
end

def letter_check(word)
  word =~ /[a-zA-Z]/
end

def total_calculation(amount_tendered, total_price)
  amount_due = amount_tendered.to_f - total_price
  if amount_due >= 0
      puts '==================='
      puts"Change Due: $#{"%.2f"%amount_due}"
  else 
    amount_still_owed = amount_due * -1
      puts puts '==================='
      puts "The customer still owes: $#{"%.2f"%amount_still_owed}"
  end
end

item_total=[]
number_check=0
puts "What is the price of the item?"
item_price=gets.chomp

while true
  if number_check(item_price) == 0
    item_total.push(item_price.to_f)
      total_price = item_total.inject() {|sum, price| sum + price }
        puts  "Total Price: $#{"%.2f"%total_price}"
          puts "What is the sale price"
            item_price=gets.chomp
  else number_check(item_price) == nil 
    break
  end
end

if (item_total.length > 0 && letter_check(item_price) != 0) || item_price == "Done" || item_price == "done"
  puts "=============="
    puts "Total Price: $#{"%.2f"%total_price}"
      puts "Here are your list of items:"
        puts item_total
          puts "What is the amount tendered?"
            amount_tendered=gets.chomp.to_s
end
  if number_check(amount_tendered) == 0
    total_calculation(amount_tendered, total_price)
      puts Time.now.strftime("%m/%d/%Y")
        puts Time.now.strftime("%I:%M%p") 
  else 
    number_check(amount_tendered) == nil 
      error_message
end

The while loop could be further simplified by removing the nesting of code within an if-statement like so:

while true
  puts "What is the sale price"
  item_price = gets.chomp

  break if number_check(item_price).nil?

  item_total.push(item_price.to_f)
  total_price = item_total.inject() {|sum, price| sum + price }
  puts "Total Price: #{formatted_money(total_price)}"
end

I'd also recommend to spend time to make sure that variable names are very good descriptions of their value. For instance, the variable total_price is somewhat misleading since it does not actually hold the value of the total price. Instead, this would be better if it were named something like item_prices or prices, signifying that it is a collection of more than one price.

item_prices = []
number_check = 0

while true
  puts "What is the sale price"
  item_price = gets.chomp

  break if number_check(item_price).nil?

  item_prices.push(item_price.to_f)
  total_price = item_prices.inject() {|sum, price| sum + price }
  puts "Total Price: #{formatted_money(total_price)}"
end

This will make the code much easier for other developers to read and understand.

A good habit to get into is to try and create methods that help isolate logic/computation and make the code easier to read and understand.

This is sometimes even appropriate when the code that will be in the method is only one line long. An example of this would be changing line 33 to take advantage of a calculate_total method like this:

def calculate_total(item_prices)
  item_prices.inject(0) { |sum, price| sum + price }
end

# ...

total_price = calculate_total(item_prices)