CODEWITHSUNDEEP
pythonfunctionmath
user1210588
user1210588

Reputation: 67

Python function that calculates membership price

I'm struggling trying to find out how to add the math into this function:

Question: Write a program which first defines a function with signature calculateFathersDayPrice(price, isMember). The function should return 95% of the price if the user is not a member and 85% of the price if the user is a member (i.e., as indicated by isMember). Your program should then prompt for a price and whether or not the user is a member (you can assume that the user enters “yes” or “no”), call calculateFathersDayPrice(), and then print the price returned by the function.

My code so far:

def calculateFathersDayPrice(price, isMember):
"""Prints price*0.85/100 if isMember is True, prints price*0.95/100 if isMember is
false
"""
if isMember:
    print  price * 0.85/100
else:
    print  price * 0.95/100 

price = raw_input ("Please Enter Price of Item: ")
isMember = raw_input ("Are you a member?: ") 
print 'price:', price, 'Member Status:', isMember
print calculateFathersDayPrice(price, isMember)

Upvotes: 2

Views: 462

Answers (4)

gfortune
gfortune

Reputation: 2629

Couple issues to point out here and most of the are noted by other answers already, but missing an important one so I'll wrap it all up in one answer. First, the function...

def calculateFathersDayPrice(price, isMember):
    if isMember:
        print  price * 0.85/100
    else:
        print  price * 0.95/100
  1. As noted by Aayush, you should not be dividing by 100. Perhaps you were thinking price * 85/100? Regardless, the most straightforward approach is simply multiplying by 0.85 and 0.95.
  2. Instead of printing the value in the function, you've been asked to return the value. It is good design to separate "presentation" logic from "business" logic and in this case, the business logic is the calculation. Your function performs the calculation and passes the results back to the main part of your program which handles the actual display. To return a value, it's simply return some_value.

Here is a altered version of your function with those two changes.

def calculateFathersDayPrice(price, isMember):
    if isMember:
        return price * 0.85
    else:
        return price * 0.95

Finally, as noted by Andrey, you need to handle the user input and do something useful with it. You need to decide what kind of values to accept from the user and what you're going to do if they enter something bogus. After your line isMember = raw_input ("Are you a member?: "), you need to add a little code to turn the user's input into a True/False value in Python. Also, what will you do if they answer "Feta cheese is nasty!" as a response to your question? Is that True or False or do you ask them again for more reasonable input?

Upvotes: 1

hexparrot
hexparrot

Reputation: 3427

I tend to encourage no side-effects in functions, so you can use 'return' rather than 'print'.

def calculateFathersDayPrice(price, isMember):
    if isMember:
        return price * 0.85
    return price * 0.95

price = float(raw_input("Please Enter Price of Item: "))
isMember = raw_input("Are you a member?: ").lower() in ['true', '1', 't', 'y', 'yes']

print 'Member Status: %s' % isMember
print 'Price: %.2f' % calculateFathersDayPrice(price, isMember)

This will check if the answer is one of the supplied true-values and then calculates the price based on the isMember status. Finally, using string formatting, you get the result with the proper amount of decimals.

Upvotes: 1

Andrey Sobolev
Andrey Sobolev

Reputation: 12713

If you assume that the user enters yes or no being asked if he/she is a member, then you should evaluate his/her answer to True or False. Your program now prints price*0.85/100 in any case. And yes, there is no need in division by 100.

Upvotes: 0

Aayush Kumar
Aayush Kumar

Reputation: 1618

I don't quite understand what you're asking.

Additionally, you shouldn't be dividing by 100 again. It should be: print price * 0.85 and print price * 0.95 respectively.

Upvotes: 1

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