Question

In problem set 1, part b, what is the reasoning behind having "balance = initialBalance" appear both in "#Initialize state variables" and after the while statement?

Answer 1

Can you paste the code?

Answer 2

# Retrieve input
initialBalance = float(raw_input("Enter the outstanding balance on your credit card: "))
interestRate = float(raw_input("Enter the annual credit card interest rate as a decimal: "))

# Initialize state variables
monthlyPayment = 0
monthlyInterestRate = interestRate/12
balance = initialBalance

# Test increasing amounts of monthlyPayment in increments of $100
# until it can be paid off in a year
while balance > 0:

monthlyPayment += 10
balance = initialBalance
numMonths = 0

# Simulate passage of time until outstanding balance is paid off
# Each iteration represents 1 month
while numMonths < 12 and balance > 0:

# Count this as a new month
numMonths += 1

# Interest for the month
interest = monthlyInterestRate * balance

# Subtract monthly payment from outstanding balance
balance -= monthlyPayment

# Add interest
balance += interest

# Round final balance to 2 decimal places
balance = round(balance,2)

print "RESULT"
print "Monthly payment to pay off debt in 1 year:", monthlyPayment
print "Number of months needed:", numMonths
print "Balance:",balance

Answer 3

# Test increasing amounts of monthlyPayment in increments of $100
# until it can be paid off in a year

There is the answer. They are doing this more than once.

Answer 4

So since it is a loop the variable needs to be redefined each time it reenters the loop?

Answer 5

By generating the variables outside the loop, they have a larger scope. If you initialize a variable inside a loop, it only exists inside the loop. By doing it outside the loop, it has a more global scope. That is the reason for the first one. The other is in the loop and resets it each time.

Answer 6

Ok that makes since, thank you!

Answer 7

np. have fun!