Ask the Customer: input() and Numbers That Arrive as Text

Sam changes prices from the back office, and Sam types them the way people say them: 3.25, in pounds. The till keeps pennies. There's a new file for this, price.py.

int("3.25") gives a ValueError, because int only reads whole numbers. float reads numbers with a point: float("3.25") is 3.25. Times 100 is the pennies, but floats come out a hair off, and int doesn't round, it just cuts off what's after the point:

print(4.35 * 100)          # 434.99999999999994
print(int(4.35 * 100))     # 434, a penny short
print(round(4.35 * 100))   # 435

round gives the nearest whole number, which is what a price means. In price.py, ask for the new price and print it both ways:

New flat white price: 3.25
Flat white: 325 pennies, £3.25

Press Run and type a price. The check types 4.35 among others, so the penny has to be right.

# Sam's back office: a new price typed in pounds, kept by the till in whole pennies.

# TODO (Step 3): ask "New flat white price: ", turn the answer into whole pennies (round it),
# and print:
#   Flat white: 325 pennies, £3.25

provided for you:order.py

Back to order.py. A customer orders flat whites and croissants, so the till asks three questions, in this order: the name, then flat whites, then croissants. Then it says the total:

Name: Sam
Hello, Sam! What can I get you?
Flat whites: 2
Croissants: 1
Total for Sam: £8.85

The total line replaces the "flat whites come to" line.

Typing three answers every time you press Run gets old, so Run now uses customer.py, which plays a customer: python3 customer.py Sam 2 1 answers Sam, 2 and 1 for you. To serve someone else, type it yourself in the terminal with other answers, for example python3 customer.py Alex 1 3. You can still type python3 order.py and answer the questions yourself.

# Bean There's order screen. Prices are in whole pennies: 320 means £3.20.
FLAT_WHITE = 320
CROISSANT = 245

name = input("Name: ")
print(f"Hello, {name}! What can I get you?")

flat_whites = int(input("Flat whites: "))
pennies = flat_whites * FLAT_WHITE
print(f"{flat_whites} flat whites come to £{pennies // 100}.{pennies % 100:02d}")

# TODO (Step 4): ask "Croissants: " too, and replace the flat whites line with the order's total:
#   Total for Sam: £8.85

provided for you:customer.py

Priya typed her name the way people do on a small screen: two spaces, all lower case, a space at the end. Run it:

Name:   priya shah
Hello,   priya shah ! What can I get you?

The till repeats exactly what came in. You tidied names for cup labels in your first quest: .strip() takes the spaces off both ends and .title() gives every word a capital. Tidy the name as it arrives, so every line after uses the tidy one:

Hello, Priya Shah! What can I get you?
...
Total for Priya Shah: £14.50

The quotes in Run's command keep Priya's spaces: ' priya shah ' is one answer. The check serves four customers who typed their names four different ways, and tells you how many came out right.

# Bean There's order screen. Prices are in whole pennies: 320 means £3.20.
FLAT_WHITE = 320
CROISSANT = 245

name = input("Name: ")
print(f"Hello, {name}! What can I get you?")

flat_whites = int(input("Flat whites: "))
croissants = int(input("Croissants: "))
total = flat_whites * FLAT_WHITE + croissants * CROISSANT
print(f"Total for {name}: £{total // 100}.{total % 100:02d}")

# TODO (Step 5): tidy the name as it arrives, so "  priya shah " becomes "Priya Shah" everywhere.

provided for you:customer.py