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ZAMYLA CHAN: Let's get some
cash in Python this time.

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The logic for the cash
problem is remaining the same.

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So is the process.

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We'll want to prompt the
user for an amount of change.

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And then using an algorithm that
always uses the largest coin possible,

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we'll keep track of the
amount of coins used

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and then print that
number back for the user.

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So let's compare a couple of things
as we translate from C to Python.

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As we translate from C to Python, many
functions remain the same, for example,

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get float.

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However, in C, we had to hashtag
include the cs50 library,

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and in Python we're going to import it.

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In terms of validating input, in C
we used the do while loop structure.

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Now in Python, we don't have
a do while loop available,

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but we do have a while loop.

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So let's see how we can
modify a while loop in order

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to mimic what the do while loop did.

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Consider this snippet of code.

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While true I'm going to prompt the user,
and then if a certain condition is met

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I'm going to break.

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This first section ensures
that we prompt the user

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at least once because the condition
for the while loop is true.

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Then, we have a condition.

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And if that condition is
met, executing a break

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will break us out of our while loop.

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So think about what that
condition must be in order

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to accept only valid
input from the user.

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And with that input from
the user in dollars,

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we yet again want to convert that
to cents, using the round function.

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Modulo math applies yet
again here in Python.

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So if you didn't get a chance to
explore using the modulo operator

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when you implemented this
problem way back in C,

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then perhaps challenge yourself
to use modulo now in Python.

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The modulo operator returns
the remainder after division.

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Take a look at these examples
to see how modulo works.

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In Python, you'll use two slashes
for integer division and one slash

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for floating point division.

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So try to see if you can use a
combination of modulo and division

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to implement this cash algorithm.

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The very last step is to print
the number of coins used.

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In C whenever we wanted to
print the values of variables,

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we had to pass in a place
holder to the printf function.

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In Python, all we have to
do is pass in the variable

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itself into the print function.

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And there we have completed the problem.

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My name is the Zamyla.

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And this was cash.

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