Question

The last thing we will learn about in python is functions. Functions are a great way to organize your program - we use them to write code that is executed only under certain circumstances - for instance when you're using Amazon, any of the following are likely functions within their program:

- Add item to cart, determine arrival date,  create a new address, compute taxes, compute shipping charges, charge credit card

Because you can write a task-specific function once, and ensure it works properly, they allow you to break down and write large programs.  

Programming- Python

You will use all the programming techniques we have learned thus like- including if statements, loops, lists and functions. I leave the bulk of design up to you (hint - think A LOT about it before you start programming!!) but it should include all of the following:

The basics - Add items to a cart until the user says "done" and then print out a list of items in the cart and a total price.

- Ensure the user types in numbers for quantities
- "Hardcode" the price of items into a list and pick from it randomly for each item
- Get the user's name and shipping address
- Separate functions that compute tax (bonus - different based on shipping state?) and shipping costs (based on number of items?), and returns their values to the main program
- Bonus: Set up a list of lists with all the items/prices in your store and only let users pick from that list

Answer 1

Below is a screen shot of the python program to check indentation. Comments are given on every line explaining the code.

Below is the output of the program:

Below is the code to copy:
#CODE STARTS HERE----------------

def add_to_cart(inventory,cart): #Add items to cart from inventory
   print("ITEMS\t\t\t\tPRICE in $")
   for item in inventory: #Print items in store
      print("{0:15}{1:10}".format(item[0],item[1]))
   print("To add items to cart, Enter item name with quantity separated by space. "
        "Enter 'Done' to stop")
   while True: #Loop until user enters done
      inp = input() #Take input
      if inp.lower() == "done":
         break #Exit when user enters Done
      item = " ".join(inp.split()[:-1]) #Get item name
      try:
         quantity = int(inp.split()[-1]) #Get item quantity
      except:
         print("Quantity must be an integer") #Check if quantity is an int
         continue
      price = 0
      for x in inventory: #Find inventory for entered item
         if x[0] == item.lower():
            price = x[1] #Get its price
            break
      if price == 0: #IF item not in inventory, print message
         print("item not in inventory")
         continue
      else: #Add item to cart
         temp_list=[item,quantity,price*quantity]
         cart.append(temp_list)
   total = print_cart(cart) #Print cart
   return cart, total #return values

def print_cart(cart): #Prints cart itemms with total value
   total = 0
   print("ITEMS\t\t\t\tQUANTITY\t\t\tPRICE in $")
   for item in cart:
      print(item[0],"\t\t\t\t",item[1],"\t\t\t\t\t",item[2])
      total+=item[2]
   print("Total : ",total)
   return total

def tax(total):
   rate = 10 #Change rate as required. rate is in %
   return total*rate/100 #return tax

def shipping(cart):
   items= len(cart) #Adds $5 per item for shipping
   return items*5

def main():
   cart = []
   total = 0
   #Inventory of items in store
   inventory = [["mobile",100],["laptop",150],["monitor",40], ["router",24],["processor",15],
             ["graphic card",56],["mouse",10],["keyboard",5]]

   while True: #Loop until user exists
      print("\nEnter coice:\n1. Add items to cart\n2. Show cart\n3. Checkout\n"
           "4. Exit")
      inp = int(input("=> "))
      #CAll respective functions
      if inp == 1:
         cart,total = add_to_cart(inventory,cart)
      elif inp == 2:
         total = print_cart(cart)
      elif inp == 3:
         tax_cost = tax(total)
         shipping_cost = shipping(cart)
         total = print_cart(cart)
         print("Tax: ",tax_cost)
         print("Shipping: ",shipping_cost)
         print("Grand total: ", total+tax_cost+shipping_cost)
      elif inp == 4:
         print("Thank you for shopping with us!")
         break
main()
#CODE ENDS HERE------------------